Played with 4g for an hour on Friday. Just baseline rallys with a hitting partner. Didn't like it. At all. Felt a bit mushy at first. After 30 minutes felt very mushy. Was hitting with someone that doesn't hit with a lot of power, so I was generating all my own. Was a effort to keep the swing speed up to keep the ball spinning.
I hear the tension maintenance on 4g is great... but its not worth it for me. I don't like the feel at all.
So far Topspin Cyberflash is the way to go. I'm going to try some Dunlop ICE in it next.