Well I have only use 1 FE so far, guess what, MAMEWAH!
It only runs at 640x480 so you don't have much choice there...it looks OK, text flickers slightly as do some screenshots (lots of 1 pixel lines). I have not yet tried increasing the font size / different fonts but I suspect this could eliminate a lot of flicker.
My WIP version allows me to change resolution, so I changed to 640x288 and yes, it looks perfect! Of course it means less screen area to display stuff (and it looks a bit stretched) but works very well.
I've noticed since using the ArcadeVGA, that when quitting a game, the wallpaper/taskbar sometimes flicks up briefly. I'll try and find away to fix this.
Anyone else tried their FE's yet??