AZZA is such an under rated brand, but i have seen some of their cases, and they look good, and this is no exception. it has more expandability, more fans, bigger fans, quieter fans, looks cooler, and cost less, therefore go with the AZZA and the rest of my build.
none. micro boards are just smaller and they are backwards compatible with atx cases, but your case supports in anyway. you might have to adjust a few risers on your case, but that is it. it is actually a very good board, just used it in a build.
As for the video card, I'd definitely recommend the 5770 over the 4870, because you're obviously planning on keeping this machine for 2-3 years, right? I mean, you're just building it now. So b that timeframe, DX11 will come in handy and a 4xxx card will likely start getting obsoleted for the real high-end stuff.