Your experience with the P910 isvery similar to mine, with one notable exception. I too became uncontent with my T600 and made a P910 impulse purchase, but I chose to go back to my Treo and put my P910 on eBay.

My personal observation is that the SE is a very solid phone although I feel more comfortable with the Palm OS. Also I believe the Treo is faster than the 910. The deal breaker for me though was the form factor. That fold-down keyboard may be functional but it doesn't even come close to the Treo's.