DC Rainmaker posted his in-depth review of the Garmin Fenix3 Multisport watch:
http://www.dcrainmaker.com/2015/03/garmin-fenix3-detailed-review.html
TL;DR - The FR920XT is smaller and maybe still better for pure run/bike/swim but the new Fenix3 supports the 3rd party apps & widgets, looks a lot better (more like a high end watch than a sports watch), and better features for other outdoor/hiking/skiing activities.