Don't have one, but I've driven one. Let's put it this way. I'm 5'6'', 160 pounds, and the Maxx was a tight squeeze for me. WAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAY to small a car. Get the regular Malibu, or better yet, a Monte Carlo SS.
I've rented the Malibu Maxx a couple of times and thought it was a decent car, particularly for a family. It is very competitively priced too. You can read my review of a 2005 Malibu Maxx on Epinions at the link below.