The only really objective way to view them is have a 650 and 700 side by side or be a user of the 650 and try out the 700. I think you will find the 650 looks better and works generally better, but the 700 is good if you really want to work with the mini Office products. Lots of choices on the 650 to open and edit Office documents, but they still don't look and feel like Office.
It does suck to be stuck with Verizon. They have a good network, but they really charge you for it when it comes to data. Probably an excellent choice if your work is going to spring for a PDA phone, but for personal users I would venture a guess that the 650 is a far better value. Especially now as the prices are coming down on the 650.