anybody have experience with garmin 500 and 520? healthpack was very kind to let me use her extra 510, and I'm really digging the upgraded features, except the touch screen. The 520 doesn't cost that much more than the 510, and is more refined in just about every way, especially the map feature, which I like to use for training. After some research, I'm considering it.

A couple of questions:
how much does the battery life differ? with/without bluetooth? If it drains significantly more battery, it uses up more cycles, and the capacity depreciates faster.

any weird function quirks? my 500 sometimes is slow at switching screens, and sometimes saves rides really slowly. There are other quirks, which I can only assume has to do with the firmware, not the hardware, but not certain. what quirks does the 520 have?