Reversing transactions on a large scale

Right now we are running mysql as that is what was there when I
entered the scene. We might switch to postgres, but I'm not sure if
postgres makes this any easier.

We run a couple of popular games on social networking sites. These
games have a simple economy,and we need to be able to time warp the
economy back in time, which means reverting a whole lot of
transactions and inventories. Our games generate around 1 million
user transactions per hour, which results in inserts/updates on 4
times that many rows. Using PIT recovery would be a very reliable
way to accomplish this, but I'm wondering how long it would take. If
it takes a full day to roll back an hour of game time, then I need to
find another solution.

Chris