Well, I have to say I’ve thoroughly enjoyed my 610 since it arrived yesterday – worked lovely on my 30 minute sunny lap around the park. Obviously I won’t be using it when it rains 🙂
GPS pickup is about twice as fast as the 705, the vibrate alert is far better than annoying beeps on laps and the touch-screen has worked ok. TBH I’m not 100% why it’s got the touch-screen, it certainly wasn’t the reason I bought it and time will tell how robust it is – you could certainly emulate all the functionality with a couple of buttons.
I wanted a decent watch-shaped GPS – the 305XT has the same features (+ some additional power settings I think, and waterproofness) but it really looks like an edge strapped to your wrist and isn’t a great deal cheaper – if I was interested in triathlons I’d have maybe gone with the 310XT but for running and maybe cycling (not sure if I’ll sell my 705) it looked to be the better bet. The 405/410 sits a fair bit higher than the 610 on the wrist and the issues with the bezel are numerous.
As far as robustness – about 1/2 my current run is off-road and it’s had a couple of knocks / dealt with whipping branches ok, not exactly the depths of the muddy winter as tests go but it’s unscratched which is more than I can say about my arms and legs. I’m sure you could get a screen protector for it if it worried you.
The screen is also slightly recessed – the 310/305 have known issues with screens cracking as there’s no protective bezel / lip. I think the new Nike watch also has this problem.
it’s also got some quick-switch functionality to toggle between cycling and running easily – haven’t had a chance to give that a go yet.
All good so far and preferable to my old Suunto.