If you go as Shizuo from DRRR! then you'll probably be recognized more and get more attention because of the bigger fanbase. However, you'll certainly make the day of any Girls Bravo fans to see one of the lesser cosplayed characters of a lesser cosplayed series.
And hell yeah Animazement!
Ahaha the reward of getting to go to Animazement is the only thing keeping me sane while finishing up my classes right now.
I totally second what Valalaraptor said. There are pros to being easily recognized as Shizuo because more know of him, but it can be really damn awesome to hear someone tell you something like "I didn't think anyone here would cosplay that!" I say just go with whoever you like, and who you can get a decent cosplay of put together.
I dunno about the other character, but Shizuo is a relatively easily cosplay to mod. I'm guessing that other character is from a slice-of-life sort of show, so his outfit shouldn't be extremely difficult.
Best of luck whoever you choose!