Inspite of quite a few mentions that the 680 falls short of the other models, I think it delivers great value of money with most functionality that a normal PDA user would need.

The 750 – good ..but nothing too different from the 680. Might as well wait for a more feature packed model to shell out the premium of a 750.

Am waiting to get my hands on one of them.

Some good reviews :

http://socialmedia.vox.com/library/post/treo-750-launched-on-cingular-in-the-us.html
http://dukecarico.com/Palmspec.htm
http://www.palm.com/us/products/compare/index.html