The physics are actually pretty good for an arcade shooter.
No longer can you haul the hand-brake on at 100mph and do a perfect slide around a corner, which has got some GTA kiddies in a tizz.
All the cars now have lots of inertia and weight transfer (albeit a little exagerated) but overall the physics are VERY nice.
I had a couple of nice situations,
1) flying along chasing a guy on a motorbike I wanted to steal, we came up to a dock on the waterside, he noticed, I didn't he swung the bike round and ended up level with the dock, I proceeded to hit him, forcing me out of the windscreen, and him and his bike into the water with me following close behind in a superman pose.
2) Riding a moped back to my safe house when the traffic lights go red, the 2 cars in front slam the anchors on, I hit the rear of the 2nd car, making him hit and damage the car infront, and sending my flying over both cars and landing on my back infront of the first car.
Doesn't sound that ground breaking in text, but the way it all works is lovely..