The F2012 seemed to have no rear end stability / downforce so will wear it's tyres quickly in the race. It was also eating the front right. I don't ever remember seeing a car throw chunks off it's own tyre into the cockpit.
The Red Bull looked pretty well balanced in Vettel's hands but Webber was struggling a bit. It also seemed to chew the front tyre a little too quickly.
Button was struggling with the rear end but otherwise looked okay. Hamilton looked nicely balanced and had plenty of pace. Could have gone even quicker if not for locking his front left into turn 10 (quite a common thing across the grid today).