I am on my second Casio Triple Sensor, and love it. The first one still works, but one of the little arms that hold the band got broken, so I can't wear it anymore. Compass seems to be pretty accurate. Tthermometer is so-so, you have to take the watch off and lay it down for 20 min or so to get a reading, which is not worth the trouble most of the time. Altimeter is my favorite part, except of course the time keeping. It seems to be very accurate, as long as you re-set it whenever you are at a known altitude. I assume (hate that word) that the barometric readings are similarily accurate.

If I had one complaint it would be the backlight, which just isn't bright enough for my old, worn out, eyes. Costso has 'em for the best price I have seen...