Maxi II is part of the ROG, Republic of Gamers, so it has more options for overlocking, so chances are you'll be able to overclock better than P5Q Deluxe. I'm not sure component wise it's that much different compared to DX, the board layout looks similar in terms of core components. You also get a sound card if that's important to you. It may take some sound processing burden off the CPU.
As for SATA port, it's no big deal