I have the 201, which is the same unit as yours (I believe) but has a rechargeable battery. The battery life in mine is about 14 hours. The only problem with mine is that if it goes dead, it's dead unless you recharge it. However, for day hikes or even overnighters it works fine.

I agree that it is pretty handy to have the unit strapped to your wrist and be able to see your progress at a glance. I have one screen with pace, distance and elapsed time and the other screen with clock and elevation. It even seems to pick up under a shirt sleeve although I haven't really had to worry about that in AZ yet.

Chad