I just played TS4 against TS3, and wow, it's striking how much better TS4 is. Movement is loads better, the game speed is much better. Serves are much better. Realism is much better, and the crowd is on a different level. Yes, TS4 still has it's quirks: players are sometimes slow to react, but nowhere near as unresponsive as TS3.
And, the game feels more like real tennis. In TS3, you couldn't hit off the rise. When you play Nadal, all he does is go forehand to backhand all day (well, forehand crosscourt), even if you are David Nalbandian. In TS4, Rafa plays more like Rafa.
And when I played against Roger with Rafa, Roger played like Roger. He pressed. When he hit it deep, I had to wrist flick it up, and even then it was short, a ball that Roger could attack.
Much, much better game, at least from my initial playing.
Gameplan: Get it deep, wait for the short ball, then come in.
(2) Volkl C10 Pros