I love this watch. I needed an altimeter for adventure racing, and i didnt want to spend 3 or 400 bucks on a watch. during a race, i check the calibration 2 to 3 times, depending on the length of the race, and this watch stays accurate very well. I find the altimeter extremely reliable as long as its calibrated before use.
its also super durable. this has taken plenty of tumbles with me and it still looks awesome.
2 cons though -
1 is battery life. it seems to eat through batteries relatively quickly, but i do use it often, and battery changing is quick and easy.
2 is the bulk. its a thick watch, I understand that this is going to be an issue with most altimeter watches, but when on the moutntain bike, the watch bounces around on my wrist and often takes some skin off. when im on the bike, i usually turn the watch face to the bottom of my wrist to avoid this. A handlebar mount will also fix this problem.