I haven't played a lot with the 99, but I prefer the 99S. It's fun to play with because it's so different than anything I've hit before (other than the 105S, which I playtested. I prefer the 99S over the 105S, too). The most interesting thing to do was to start off with the regular 99 then pick up the 99S. The difference is immediately noticeable, and I enjoyed the lively feel of the S and watching the ball dive in when I didn't expect it to.