Tried the demo two days ago (pre-ordered the game a few weeks ago).
Everything looks and feels very nice in my opinion. The cars have a good feeling of weight to them and the cockpit view doesn't feel as "dead" as before. There's some shaking and so on... good sense of speed, etc. At first it really felt like an awesome improvement over FM3.
But the steering correction, whatever it is exactly... i hope they'll fix this, but i wouldn't get my hopes up about it... most likely we'll just have to live with it again...
There's auto counter steer, but this time around it's somehow more annoying... not sure what it is exactly, but in FM3 i never had a problem to keep the cars on the road even with the "hidden" steering aid. In the Forza 4 demo, i often get some very nasty snap back oversteer effect when trying to drive the cars sideways. Never had this problem in LFS, Enthusia, GT, FM 1-3, etc... but in this demo it's terrible.
Meh, it'll be fun for racing anyway... still quite disappointed about this however, especially after they said it wouldn't be there anymore (steering assist) in simulation mode.