My comparison of the 300 and 350 was at the Best Buy store, and I didn't see the same thing as many others on this thread.
My PRS300 Pocket was MUCH clearer and a better contrast than the touch-screen 350 in the store. Some of the italic printing was very faint on the 350, but not on my 300.
Maybe the store unit was a problem viewer, but there was nothing that made me want to upgrade. I'll keep my older Pocket, thank you.