No. I got my N900 non-sim-locked, brand-new, and I still use it daily. Going to go for something else when I find something good enough, but nothing on the market at the moment is worth switching over to. The only complaints I have about my N900 is the lack of quality software, and I wish it'd have larger screen.

EDIT: As a clarification, I'd quite want a tablet-PC with sort-of-phone-capabilities tacked on it instead of a phone with sort-of-tablet-pc-capabilities, with REALLY large screen.