Which one would you choose. If you were to get one for free, which one? And please explain why.

Which one is more comfortable? Which one has more/better features? Which one looks better?

2010 GL. It is comfortable, luxurious, and hell, it's a mercades!

I'd go with the Audi, personally. I'm a big Audi fan and the Q7 is one of my favorite SUVs. I think it looks unbelievably good with the LED headlights and tailights. Some people say it's a little on the ugly side, though. The interior is big and practical, with room for 7 (obviously). The interior quality is fantastic and it looks great. It's pretty good in the snow, too, with it's four wheel drive system.

Do some research of your own. Some places to check out would be:
Yahoo Autos
Cars.com
Edmunds.com
KBB.com

Also, look up some reviews on YouTube.
Hopefully helps.

Good luck!