My wife and I drove the Q7, XC90, and MDX on consecutive days and ended up ordering the Audi. We went into it with an open mind since we currently own or have owned vehicles from each manufacturer, including the previous gen MDX. In the case of each of three companies in question, the ownership experience was good, so we tried to be as unbiased as possible. The odd car out was clearly the MDX. It brought a knife to a gun fight and the Volvo and MDX are superior vehicles as far as overall driving experience and proverbial fit-and-finish. We previously owned a 2008 MDX, and I think I actually preferred that car to the newer version, but it has been a while since we owned it so maybe reality doesn't match my recollection. The MDX just seems to be cheaper than the previous generation, and I suspect that it was the goal of Acura to cut costs when they moved production to the US from Canada. The MDX is a decent vehicle, but I say the only place where it betters each of the others is engine smoothness vs the Volvo. Overall, the MDX is meh, and given that we expect to own the vehicle for approximately 6 years, we decide to spend extra.
Next up was the X90, which by far the best looking car of the three. Volvo nailed this one in the exterior design department, the interior is very nice, and the seats are typical Volvo (excellent). The MMI is decent and the learning curve is fast. Where the Volvo falls down is engine smoothness - it cannot compare to a V6. It doesn't matter that they've SCed and turboed it. Power is decent, but I always knew that I was driving a 4 cyl that has to work hard to motivate 5000 lb. Handling is competent and overall driving dynamics are very good. Third row access was the best of the three and space was decent enough. I question the durability of the this powertrain given that it is new and unproven, and I question how it would hold up for my six years of ownership. The message boards are also full of owners that are dealing with teething issues. At the moment I am not prepared to gamble with my money on this car. If it had a V6 and a few model years under its belt, it would have been a tough decision.
The Q7 is the best overall package when compared to the others. Not as nice to look at when compared to the Volvo, but the interior is the equal of the Volvo and the seats are also excellent. I'm used to Audi's MMI, so there is no learning necessary. VirtualCockpit is excellent and I like the user configurable screens. The interior is vault quiet with very little wind noise or road noise, and is the better of the other two when it comes to NVH. The powertrain is proven (the 3.0 sc being around since 2009) and the 8 sp auto is excellent (same one as in my A6). The only negative to the car relates to the 3rd row, both access and space. I find access cumbersome and the space is marginally below the others. The 3rd row will see spot duty carrying preteens, so we can live with it. As they get older it can be used as punishment.
We went with the Progressiv trim level with Bose, sun shades and hitch as the only options, so it comes in substantially less than their tester. I gave up the urge to upsize the wheels and stuck to the standard 19s.
Others have mentioned body-on-frame competitors, but this substantially smaller and cheaper than an Escalade, and in comparison the Audi sips fuels. It will run rings around the Caddy and be the equal of it in a straight line. If it was 2006, I might consider the Lexus GX. No comparison there. The max towing rating on the Q7 is 7700 lb which is pretty decent.