First, as a very happy former Treo 300 user, I'd have to say I love the 600.

As many others report, battery life shows a huge improvement.

My talk time seems to match the 4 or 5 hours we expected from the specs, but I'm surprised to see how much battery life on the Web has improved. I seem to be able to browse for many hours and still have plenty of battery left on the indicator. Further, I always had problems with especially short battery life on the 300, whenever I left the Web connected between surfing sessions.

Two things seem to have changed in this area on the 600.

1) Leaving the web connected, now seems to have an insignificant effect on battery life.

2) The Internet Connection seems to have no trouble staying connected, and maintaining that connection between sessions. (With the 300, I'd often lose that connection after brief periods of inactivity.)

This is really an excellent device is many ways, and one, that I believe will be very successful.