The best on the game are probably those with over 1000 total spars at an 8:1 minimum ratio. I think includes Prado, Ares, Rufus, Extrav, and myself. There's probably more that make that cut and I just don't know of them. I only recently started playing actively again. Unleash and David will be up there when they spar more and Zeross could probably also be there.

Shannon is the hardest player for me to spar 20% of the time, then probably an average of a 3-hit win for me the other 80%.
Comyt is probably the best iPhone sparrer, but that's as if to say he's probably, I dunno, the 15th best sparrer overall? Seems overrated to me and rages and cries over PC players too much.
I don't even consider defensive sparrers (like Yui) in a conversation like this. There's obvious situations where you'll want to draw someone in to be aggressive offensively against you, but boring a player to death is desperate and not much fun to me.

These are my thoughts that I bump this thread with.