Robredo. Good enough to win here and there, but not dominant. Solid all-around game but no particular awesome shot. One handed backhand that occasionally rips a good winner. Really good slice. Quick feet. Serves consistently in but not blasters. Inside out forehands from time to time. Mostly a...
Dolgopolov losing to Go Soeda in Atlanta doesn't really create any sort of good press for spin racquets; although I think they can be quite effective and fun. That said, I'm not playing tour level tennis.
You could always try serving with your arm already cocked in the back scratch position. Granted it feels awkward and probably looks ridiculous, but it's a legal serve and it'll give you 15mph easy. I do this in practice sometimes. The weirdest part for me is just having the tossing arm out there...