Don't buy a MOJO just for OUYA. Buy it because you want it. The MOJO is a T4 so performance is going to be better on games that currently have issues, maybe you'll get more graphically out of the few titles that need a little more horsepower but it shouldn't be anything earth shattering since there aren't many that take advantage of higher end shaders and all that.
It wasn't long ago that only 40% of the games were OE compatible, I don't know what the number is now but I doubt it's much higher. Maybe 50%???? Do not quote me on that number.
Sideload and root I'll leave for someone else who does that stuff, to answer.
And the OUYA does not require FAT32. It's recommended but not required. There are members using EXT. See this thread: http://ouyaforum.com/showthread.php?...ommended-Specs
We don't seem to have many MOJO owners or they're some of the members who don't post for whatever reason, I'm inclined to believe it's lack of owners more than anything else.