I`ve had both, and certainly the 12s have a greater clarity on the notes but for me after a while I found this to be a bit sterile sounding so moved to the 10s but annoyingly I couldn`t coax the aggressive highs from them that I wanted, it was a case of near but not quite, so I went back to the 12s.
Bear in mind my sound was like a cross between Lemmy, Duff McKagan of Guns N Roses and JJ Burnell of The Stranglers so I was after a lot of aggression. For anything other than this I`d choose the 10s over the 12s, as to me they have more "bass cab character".