I played 9.0 mixed for the better part of the last 5 years. I never really liked it at all. It really is a different brand of tennis.
That said, I got roped into playing 8.0 next summer. I'm immediately regretting the decision. I have to play with a 3.5 woman and I'm told that it's not much fun.
"It is not enough that I succeed...everyone else must fail."