When comparing Garmin Vivosmart vs Garmin Forerunner 235, the Slant community recommends Garmin Forerunner 235 for most people. In the question“What are the best fitness trackers that pair with iPhones?” Garmin Forerunner 235 is ranked 7th while Garmin Vivosmart is ranked 16th. The most important reason people chose Garmin Forerunner 235 is:
It's quite lightweight at 1.6oz and has a large bright display for easy reading while on the move in all types of lighting conditions. It's water resistant up to 50 meters so you're safe to wear it running in all types of weather.
Specs
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Pros

Pro Smartwatch-like functionality
Vivosmart is capable of showing smartphone notifications and control music playback.
Pro Logs exercise
Pro Week's battery life
Pro Some customization options
Pro Displays time
Pro Good step counter
Pro Ideal tracker for runners
It's quite lightweight at 1.6oz and has a large bright display for easy reading while on the move in all types of lighting conditions. It's water resistant up to 50 meters so you're safe to wear it running in all types of weather.
Pro Quickly picks up a GPS signal
It picks up the GPS signal much faster than most other GPS fitness trackers available, so there is little waiting around for it to connect before you start your run.
Pro Customize the display screen to display the data most important to you
The display screens are fully customizable so you can control which stats you want to see.
Pro Extremely lightweight and comfortable
Despite the amount of hardware this tracker contains and it's large size, it's very lightweight and comfortable to wear.
Cons
Con Companion app is difficult to use
The way the information is presented is confusing and incoherent and there's no logical way to find necessary information.
Con No activity autodetection
Vivosmart does not automatically detect when you start to walk or run, you have to start and stop activity manually.
Con Reps counting feature does not work for some exercises
Reps counting feature is not reliable, sometimes it misses few reps and with some exercises it can count 1 rap, even if you did 10 reps for example. And it can't detect when you start the exercise, so you have to start and stop the counter manually. In practice I frequently forget to start and to stop the counter so after some time I simply sopped using this feature.
Con Difficult to check current time because display most of the time is turned off
In order to turn on the display, for example to see current time, you need to raise you hand and after some delay display some times turns on, sometimes not.
Other option is to double tap the display, which requires both hands.
If you frequently checking current time, it is really annoying.
Con App requires you to provide personal data in order to work
You have to register in the app providing information about your age, gender and weight.
Con App does not work without internet connectivity
It is not possible for example to enter your weight if you are not connected to the internet.
Con No GPS data is collected
Con Has trouble tracking heart rate during intervals
During interval training when there is a frequent change of exertion, the Forerunner 235 has trouble continuously providing accurate readings. It's better suited for running with a sustained pace.
Con Needs to be recharged often
Garmin states the watch has a battery life of 11 hours training and 9 days of use as a watch, which is a fairly short charge compared to other fitness trackers.
However many people have found the actual charge to be much less, often needing to be recharged every couple of days.
