I have a PS4 and I will be getting it on both the PS4 and PC when it comes out. I will be very interested to see how my current machine will handle GTA V. Like someone stated already, I do hope its not like GTA 4 for PC. But, I did read that the RAGE engine they used (which was new when they made GTA 4) wasnt actually designed to be a game engine, so they have had a few years to tinker with it hopefully by now its a much better engine. I figured they would have scrapped RAGE altogether and use a new engine for the next gen, but we will see how well this overhaul works.... I personally think RAGE is horrible. Its lack of AA support was a big killer for me.
Everyone always cites the fact that Max Payne 3 is the same engine and runs really well on PC. Granted a linear action game doesn't function nearly the same as an open world game like GTA V. I also think Rockstar knows how bad they screwed up on GTA IV and know not to do that again. They're spending a lot of time on this new release with adding a whole bunch of new things, so I'm sure they'll have spent time making it run well too.