Coming to BigBox to replace EmulationStation as my FrontEnd for RetroArch. The built in file and image management, along with the seamless (hidden CMD.exe) features go a long way to making my setup look and feel less like a computer. I just wanted to share a couple of thoughts as feedback.
1) A lot of TV based interfaces plan for a bit of overscan and have increased padding around the edges. BixBox, especially on the lefthand lists goes almost up to the edge. This makes it feel more like a Desktop App than a Set-Top Box App. I feel that if you increased the padding on the sides and top it would create a more game system like feeling.
2) The three column view (Games, Images, Details) that you use to display the game data is very information dense. The density requires more effort to interpret without adding a lot of value. The varying width of the box art and screen shots can also cause the center column to appear to be mis-aligned. My idea is that you could display the "game details" and "screenshots" in a similar manner to the back box art. You hit the flip button and they rotate in. You could potentially go all in, make it so only the box art is displayed and all the other details are flipped / rotated in.
C) This is probably should go under bugs, but I get some pretty bad slowdown slowdown and stuttering navigating the menus. This is especially noticeable when selecting the platform. Changing the transition style did not have a noticeable effect. I am running Win7 on a i7 Mac Mini with a integrated Intel Graphics chip (4000 series I think). It's got 8gig of RAM 4 of which I enabled for image catching.