depends on key features, out of things I'm interested in, in particular the 630 doesn't do power meters or strava live segments if you're interested in them.
I returned a Fenix 3 a while back, it was appalling due to the GPS issues. I think that might have improved, but I'd steer well clear based on my experience.
I've now got a 735xt, and it's excellent, really like it. Would definitely recommended.
Would also recommend the 735XT, with exception of some minor issues this watch has worked well from the beginning and continues to perform accurately and without issue.
I might give a try to the new Fenix 5 once released as the only area I would like improved on the 735 is the look of the watch. It is not bad looking, but looks like a sports watch and a little cheap compared to metal cases on the Fenix watches.
I'd also recommend the 735xt out of those 3.
the 735xt performs faster and also has more memory available for connect iq apps than the other 2 watches mentioned, I made one app where the 735xt version (26kb memory available) can do more than on the other platforms (because there's only 16kb available for f3 & 630).
When buying now I might consider buying the fr735xt, the fenix 5 or waiting for the 935xt (not released yet)
For me when the choice is between fr735xt and fenix5, I'd likely go for the 735xt because it's lighter.
I would probably go with the 735XT. I had a Fenix 3HR but due to barometer/altimeter issues, I decided to return it and get a 735XT. So far I am very pleased with it. There are some minor issues, but nothing as major as a faulty altimeter. Yeah it may not have a barometer/altimeter, but I'm fine with that because I have other features that features that are more valuable to me, mainly Strava Live Segments. Also the 630 and Fenix 3 do not support the latest CIQ SDK.
The 935XT is what people think will be released as the successor to the now 2 year old 920. It hasn't been announced and people are just guessing that there will be a successor without any details. If you talk about it Garmin will just delete the posts so it's not discussed much. We don't know when we will see such a device, how much is weighs or it's functionality. If you want a device now, go with something released and available. If you don't, then wait and there will probably be a successor to the 920xt (Garmin tend to refresh families of devices every 2-3 years), just don't hold your breath!
