My PS3 version turned up on Wednesday, and I've only managed to put about 4-5 hours into the game.
It definately stutters in places, and I tend to notice it most on the intro and cutscenes. In the actual game it hasn't been *too* bad, but then I've yet to get into the game proper.
A bit like yourself I had the choice over whether to go PC or Console, and in the end I fancied playing it on one of the consoles. There is a nice comparison over at DigitalFoundry @ Eurogamer which compares the FPS on all 3 versions, amongst other things. If it is a major issue then I'd consider buying the PC or 360 version instead.
It's worth noting there are 'occassional' glitches occassionally in the graphics on the PS3 version. More annoying is the poor target selection and the fact you can't zoom out on the view (not unique to the PS3 version though). But none of this will stop me enjoying the game.