Not exactly the same, but I just got a 650--great reader by the way!
And my husband who currently has a 900 said that he actually likes reading his technical PDFs on my 650 rather than his 900. (Screen is much clearer and zoom options are better.)
My husband is now trying to decide if he wants a 650 to replace his 900 with. He also really wants an iPad--but the price for the iPad is holding him back. With that said, when the 950s come out in November--I'm sure they'll be even better for reading technical manuals on than my 650.
Good luck with your decision.