I have a 350 myself since portability is very important, but i have to admit it was a tough choice at the shop!! 650 is fairly light and size-wise is actually pretty close to my previous 5" reader (Astak).
But 350 is truly tiny. The size in the cover (Sony cover) is 11x15cm.
650 also comes in a gorgeous deep red color.. i didnt like the pink of 350, so got silver, which is a tad boring.
So if the color is important to you, thats something else to consider!
