I switched from a Garmin Fenix2 to a Suunto Ambit3 and have been REALLY impressed. My Garmin would have GPS issues probably once every 2 weeks (Garmin replaced the watch once already and then when the replacement failed to save activities they said I was out of warranty). The Suunto finds GPS signal within seconds (when I'm indoors before a run!), and it's never lost signal during an activity.
Only negatives are that there is no vibrate feature (which I find useful for mile splits) and the software is a little clunky (compared to Garmin).
If you live in a hilly area it's probably a good idea to spend a little money and get a watch with a barometric altimeter (like the two I mention above).