I agree with ambassador about the fact that Xna is more a framework than a game engine, than mean you have to create most of your tool or use 3rd Party. They should have physics integrated but I mean is not this relevant because Ogre which is a graphic library don't have any. + it's a free package. if you want to have for example a collision library you just have to pay 49$ dollars for the submission ( haven't did so I'm not really aware of it)

But if you want to compare both of them XNA is great for developpers you can build you engine in no time and also it give you a better control without work around. It's coded in c# so you can't find a lot of inofrmation ( a7 too but it's not the same thing) and also the community is growing, so you can progress.

A7 is a game engine so it's supposed to be a complete package, but it's not. I can really judge the actual engine since I don't own it( just have the old A6).

But the reason I stop using complete package is some point it's interesting if you want to make your game and everyting but are limited to the game feature, you just wait for the other to your job, you get lazy and you don't really progress. This is my reason and I do understand why people don't want to bother writting their own tool or classes, but since my game didn't really to what I had in mind Xna was a good deal beacuse I didn't have to create all from scratch but it same time I was free enought to take the direction I wanted.