I have UTG flip-ups on my Just Right 9mm/.45 ACP carbine and they seen great so far. I am going to change the blade out in the front though, my old eyes need the help of a white lilne blade.
Ive had great experience w/ Magpuls gen1 MBUS and Troy BUIS. I really need to get ahold of a Gen2 set. They look great and are a lower profile which would make it easier to mount a scope.