Review: Fitbit Ionic vs. Garmin Forerunner 35

By | December 25, 2019

I recently replaced my Fitbit Ionic, which I wore for a couple years, with a Garmin Forerunner 35. Before the Fitbit, I wore two different Pebble models, so I’ve had long-term experience with four different fitness smart-watches.

Here are my thoughts about both watches and how they compare.

A good overall framing for this review is that the Ionic is a smart-watch with some fitness features, while the Forerunner is a fitness watch with some smart-watch features.

Fitbit Ionic

(MSRP $250, frequently available for ~$200 if you shop around or wait for a sale)

The Ionic’s marketing collateral is accurate as far as it does, so if you’re not familiar with the watch you can start by reading it. My personal highlights:

  • The high-resolution color touch screen and many available watch faces and apps are all nice.
  • The user interface is well-designed and relatively intuitive.
  • GPS, steps, heart rate, and sleep tracking all seem to work relatively well.
  • Many different types of activity can be tracked.
  • The battery life is good but not great.
  • The Gorilla Glass screen is extremely durable (after a year and a half with my Ionic the screen looked as new as the day I got it).
  • Contactless credit card payment with a watch is sweet.

Having said that, unfortunately it’s not all rainbows and unicorns…


Many Ionic users have experienced the watch spontaneously bricking itself, i.e., becoming completely dead with seemingly no way to wake it up. For some reason (Fitbit has never adequately explained it) this most frequently happens overnight, i.e., you go to sleep wearing the watch with plenty of battery time left and it’s working fine, and when you wake up in the morning the watch is completely dead and won’t respond.

My ionic self-bricked twice. The first time through some miracle I was able to resurrect it with some combination of hard and soft reset sequences on its buttons, but the second time none of those combinations worked; the watch was just completely did.

Many people have experienced this after the one-year warranty on the watch has ended, and Fitbit’s answer when they’ve complained has often been, “So sorry, here’s a 25% discount on buying a new watch from our web storefront.”

This is not acceptable, to put it mildly. If an electronic device spontaneously stops working for many people, then there’s a design defect in the watch, and the manufacturer should replace the watches regardless of whether their warranty has expired. Fitbit’s response to this issue is unethical and arguably illegal, since design defects violate the implied warranty of mercantability which is the law in most states and is not time-bound.

Magnetic charging cable

The Ionic, like many other watches, uses a charging cable that has little magnets built into its tip; these magnets stick to corresponding metal plates to hold the cable’s charging pins in place against contacts on the back of the watch.

I’ve had three different watches that use this approach to charging, so I can say with conviction borne out of bitter experience that it’s a stupid design and manufacturers should stop using it.

As you wear a watch, two things happen: the plastic on the back gets worn down by constant rubbing against your wrist; and dried sweat, sloughed off skin cells, and dirt get into the crevices and onto the electrical contacts where the charging cable is supposed to fit.

Magnetic charging has extremely small error tolerances. Once you exceed these tolerances through a combination of wear and dirt, it stops working properly. Cleaning off the dirt only goes so far.

Also, rare earth magnets are a precious resource and we shouldn’t be wasting them on smart-watch charging cables.

Syncing and notification failures

The Ionic is supposed to remain in contact with your phone via Bluetooth so that it can regularly synchronize your fitness data, display notifications, and allow you to perform actions on them, e.g., dismissing or sending a canned reply.

The Ionic’s connectivity is terrible. It regularly lost contact with my Android phone. This happened mostly when I left my phone’s Bluetooth range and the watch wouldn’t restore contact with the phone when I returned, but it sometimes happened when my phone never left my side.

This is a huge issue because I depend on my watch for notifications, i.e., my phone is in silent / no-vibrations mode all the time, and the only way I find out about a phone call or other important notification is when my watch vibrates. With the Ionic, I would frequently miss important notifications because the watch hadn’t lost contact with the phone without my realizing.

When this happened the only way to recover from it was to restart my phone. Restarting the watch, stopping and restarting the Fitbit app, and even trying to connect to the watch via Bluetooth explicitly all had no effect. This is problematic because some of the apps on my phone keep state (e.g., snoozed reminders) which is not preserved across restarts, so restarting my phone is a destructive operation.

This issue persisted for years — in fact, it got worse over time — and it’s really disappointing that the folks at Fitbit couldn’t be bothered to fix it.

Vibration strength

The strength and length of notification vibrations on the Ionic isn’t sufficiently adjustable. If you happen to be doing something “busy” when a notification happens, e.g., even something as simple as watching dishes, it’s easy to miss the vibration. Customers have been asking Fitbit for years to add more configurability, but again, they haven’t bothered.

No Google Fit synchronization

The Pebble app synchronized data into Google Fit so you could keep all your health data in one place, but the Fitbit app doesn’t, and Fitbit has not indicated any plans to change this despite — again — being asked by many customers for years to do so. FitnessSyncer fixes this, but it costs money if you want to synchronize more than a few data, and it shouldn’t be necessary.

Garmin Forerunner 35

(MSRP $170, frequently available for ~$100 if you shop around or wait for a sale)

The Forerunner 35 does not aspire to do nearly as much as the Ionic does, and that is reflected in the price tag.

  • The screen is monochrome and it’s not a touch screen.
  • There are no watch faces or apps.
  • The user interface is a bit klunky.
  • You can’t reply to notifications from the watch.
  • The sleep tracking feature doesn’t seem quite as advanced as the Fitbit’s.
  • There are only five different types of trackable activity (Run Outdoor, Run Indoor, Bike, Cardio, Walk).
  • Contactless payment isn’t supported.

Arguably, I’m comparing apples to oranges here, since there are Garmin watches in the same price range as the Ionic which don’t have most of these deficits (for example, numerous Garmin watches support contactless payment). But the Forerunner 35 is what I have, so that’s what I’m able to write about.

For me, the reality is that I don’t actually care about most of the Ionic’s nifty whizzbang features. Here’s what I care about:

Step trackingtie
Heart rate monitoringForerunnerOnly the Forerunner lets you set low and high heart rate alerts during activities.
Sleep monitoringIonicThe Ionic seems to have more accurate sleep monitoring, including a “sleep score,” though Fitbit might be claiming more accuracy than they actually have.
Battery lifeForerunnerThe Forerunner’s battery life seems to be significantly better than the Ionic’s.
ReliabilityForerunnerI haven’t had my Forerunner for nearly as long as the Ionic, so I can’t say for certain that it doesn’t have any problems analogous to the Ionic’s bricking problem, but the scuttlebutt I’ve seen seems to be that Garmin watches are more reliable.
ChargingForerunnerThe Forerunner uses a more reliable clip mechanism for its charging cable instead of magnets.
ConnectivityForerunnerThe Forerunner seems to have rock solid connectivity; it hasn’t lost contact with my phone even once in all the time I’ve had it.
Vibration strengthtieThe Forerunner’s vibrations aren’t significantly stronger or more configurable than the Ionic’s, as far as I can tell, but on the other hand, I don’t think I’ve missed any notifications yet, so perhaps it’s strong enough? Also, the Forerunner actually supports beeping in addition to vibrations, though I don’t use that feature.
Google Fit synchronizationtieAlas, Garmin’s app also doesn’t synchronize with Google Fit.

Based on the features I actually care about, the Forerunner is the clear winner. Having said that, there are a few areas I’ve noticed where the Forerunner falls flat that are worth mentioning.

1) The Forerunner can’t calibrate your stride length from indoor running. Even if you edit an indoor running activity after completing it to tell the watch what the actual distance of the run was (e.g., if you were running on a treadmill or a measured track), the watch doesn’t use that information to calibrate. The only way you can calibrate your stride is to run outdoors with GPS.

2) Notifications on the Forerunner — even common notifications from Google Calendar — often have garbled characters in them, apparently because the watch has a limited (not UTF-8) character set. For example:

I don’t mind this so much because I can usually tell what the notifications are about and I’m fine taking out my phone when I need to deal with a notification, but it’s still annoying.

3) Relatedly, the font size used for notifications is very large and can’t be adjusted, which is great when you’re running but not so great the rest of the time when you would like to be able to see more of the notification on the screen. Ideally Garmin would allow you to use a smaller font size for notifications when you’re not running.


The Forerunner is clearly a superior watch for my needs. Your mileage may vary.

Print Friendly, PDF & Email

Leave a Reply

Your email address will not be published. Required fields are marked *