Ok so we've all seen some of the leaked gameplay and everyone keeps bringing up the same thing... the car physics. I'm not going to form my opinion yet until I actually play the game for myself but anyways, I think one thing we can all agree on is the framerate. Compared to GTA 4, the framerate is DEFINITELY a lot higher in this game and it also appears to be very consistent. R* wasn't kidding in their official gameplay trailer when they stated: "There's also been a huge focus on mechanics in the game, to make every aspect as fun and fluid as it is broad. Everything from driving and shooting, to tennis and bike riding, feels fun and responsive."
So even IF the car physics aren't that great, I'm sure everything else this game has to offer will make up for it. I'm not gonna let one aspect of the game ruin the game for me. So far, I like what I'm seeing regarding the car physics/handling, as one person put it, it's GTA 4's physics with higher suspension/grip. Regardless... we will see in just a few days.