I owned the 2007 MDX Tech for a year. It isn't a terrible SUV by any means. I saw a new 2011 in Costco today and liked the changes they have made since.

My main issue with the MDX was the engine which lacked low-end grunt and the steering which was a bit disconnected. But I did like the additional room over the X5 and the reliability.

All that said, I like the X5 much better. I do disagree with others who say the X5 build quality is better. Build quality for me includes all issues and the MDX is more reliable (and more vanilla).