Yeah, you must be either doing some wild and crazy things with your GPS or you're using some pretty low quality batteries. We have a set of 4 Noma NiMH rechargeables in our 300 and each pair lasts us for pretty much a full day of constant use, with the backlight turned on the whole time. My only complaint about the 300 is the terrible basemap it comes with; just major highways over a featureless khaki background. Still, even with that, I would recommend it for a first-time cacher; 9 times out of 10, it'll bring us to within a meter of the cache, and the lack of topo features has led to some extremely interesting hikes, and some exciting terrain-conquering adventures.
thank you for your reply jon&mona
we have not yet used rechargeables. but now know what kind too look for. we have had to get in the habit of shutting it off as soon as we find the cache.
capytone