I've had this Forerunner 235 for about a week now and my first impression has been terrible. The watch itself is pretty good, but the companion app (Garmin Connect) is hideous. It has crashed several times per day, every day. It even crashes the entire phone and makes it reboot.
Just now, I did a short bike trip to work and when I decided to view my activity in Garmin Connect, the app froze and Android let me know the app isn't responding, so I hit "Close app". Then, I restarted Garmin Connect and it didn't even make it past the first loading screen before freezing up again, and then rebooting the whole phone.
Mind you, everything is working flawless on this Galaxy s5 with LineageOS 7.1.1, except Garmin Connect.
If there is nothing I can do to fix this, I will return the watch.