I see quite a few of all of the above cars, and have driven them all. Next to my garage is a bakery, which the owner has just bought a white, 3.0TDI Q7 S-Line. Brand spanking new, in white with 21" black wheels! The 3.0 is a good solid engine, seen it for many years is all the other cars Audi do (A6 etc), never had to do much more than routine servicing etc. Although cambelts are someting else! They need a computer to adjust the injector pump timing as it's impossible by eye. He had a 4.6 V8 X5 before. Went like stink but really dated now.
Personal opinion.. I think you made the right choice, Jurgen. Yes, you can get a 7 seater ML but they suffer gearbox issues. Don't think BMW do a 7 seater X5. I really do like the Volvo XC90. But overall, money no object, the Q7 is a far superior, better looking car. His Q7 has the screen, so when you reverse shows you where the car is going and as you turn the wheel shows you where you will end up! Yes it's a big car but if the misses is careful she'll be fine with it.
So, all thats left to be said is what toys has it got???