I play both. It's 6 of 1, half dozen of the other. At a 6, you play more hands, which is, I guess, more fun. At a 9, you better be sure you have the nuts, but there is obviously more money to be made. I'd guess the main difference is your range of starting hands. That said, for real money
, I play Omaha HL, and usually the 9 table, limit or PL.