For the last 15 years my Daily Driver has been a 98 VW Jetta TDI, so performance was not really part of the equation for my new DD, the CX5. The Mustang lives under a cover in the garage until spring, and my Wife barrels around in the Expedition daily.
I wasn't comfortable anymore driving my 3 kids or their friends around in a car that lacked all of the safety features of the more modern cars. If the Audi Q5d or the BMW 320dx wagon had been available, I would probably be driving one of them. I even went as far as bidding $47k for a CPO BMW X5d, and $43K for a VW Touareg TDI and didn't win either, thank goodness. The gas versions of these cars did not excite me at all. The X3 gasser just felt considerably smaller to me.
To me the CX5 was about the balance of value and safety. The back seat "feels like a couch" according to my kids, and has the most legroom of any of the previously stated cars, and a enormously lower cost of ownership.
There are many cars out there that can be better then the CX5 at any particular aspect, but I struggled to find one that balanced so many good features together into one attractive package.
Once you decide that "image" isn't as important as value, its an easy decision to go with the CX5.