I have a Fenix 2... not thrilled with it's GPS tracking software. It works, but not great. It's not very reliable for on-trail accuracy. I have to go into Google Earth after the fact and edit out all the screwy track points. Autopause doesn't work effectively. It does alright on runs because moving fast negates the "drift", but hiking is a different story.
From what I've gathered from reading many posts, it's not a software problem but an antenna problem. Supposedly Suunto's type of antenna is much better for reception.