it all depends entirely on your usage of arena/catacombs. i can get roughly 4000 or so prof points per climb in arena before i have to get help from a group. my weapons are better than average, so it takes me less hits to kill monsters...
you are allowed 10 prof points per arena monster before the hits become null-counted. meaning you can theoretically achieve 400 or higher points per level in arena.... i would advise against striving for such high numbers because that would mean a dreadfully long and boring climb.
bottom line, arena is #1 for profs, catacombs give roughly 1/10th as much per click towards prof...