I’ve the 910XT – one-size-fits-all GPS watch that does me for cycling, running and swimming. Exports .gpx etc without issue though I use Rubitrack 3 to collate all my data.
Can’t recommend it highly enough – has put up with a fair amount of abuse and still looks like new; saw me round the Spartan Beast challenge in November without a hiccup – chipped the mud off and a wipe with a damp flannel and not a scratch on it.
The only caveat being that it doesn’t really have good enough battery life to wear as a daily watch; would be ok to wear during waking hours and charging overnight but I think it’s really meant to be worn during “activity”. Doesn’t bother me but I guess for some the watch function is equally important as the GPS side. Irony being that it’s actually not too chunky to wear as a watch unlike the 310XT which looks more like a computer strapped to your wrist, rather than a watch. I charge mine at the beginning of the week and it’ll last me through until the next weekend.
(Previously I’ve had a Suunto but the GPS was a separate pod that took ages to get a signal and wasn’t very reliable. A friend at work has the Nike GPS but I think he’s now on his 3rd warranty replacement)