The first impression is very favorable for such a price. I will update this review if it proves unreliable, but the features packed into this under $40 watch are amazing. The altimeter is a little patchy, near sea level, but the barometer is on point. I've calibrated the altimeter and it's still slightly off, but here in Florida the only way I can test it is by climbing a few flights of stairs - not the best test. I'll be at 10,000ft next week and will be climbing a mountain at 12.5+000ft with elevation reference marks to calibrate and compare and I'll actually get a chance to see how well it works. The thermometer works, but is completely unusable on the wrist. It doesn't read body temp accurately (always lower than body temp) and to get an accurate outside temp you have to take it off and leave it on for about 30 minutes, basically useless but cool if you're immobile for a while. and I have no other way of judging the temperature I guess. Don't buy it for the thermometer. Consider it a bonus/chip. My favorite feature is the world clock screen. Once you have set your home time and city time zone, you can access this screen while traveling without having to set the clock. I already have this screen for Denver. So when I land there next week, I'll just put it on this screen and my time will be accurate without having to adjust regular time. Also handy if you plan to call family/friends around the world. Brilliant.