I have Fenix 3 and I LOVE IT! I had same choice as you: Garmin or Suunto..And I'm glade I made a right choice.I have software ver.8.0 now and it seems very accurate with altitude (I'm using auto calibration) and when I load view points from "Northwest Topos" I usually finding them . Don't forget to use same Grid and Datum (UTM and NAD83 in my case) on your computer software and you GPS watch.
It's good to hear some positive feedback. How old is your Fenix? Like I said, it seems like most of the negative posts I've found on these seems to be a few years old so I'm hoping the problems have been resolved. I'd like to stick with the Garmin if possible simply because it looks much better and has many more features.