Well since your doing 50/50 I would get the Agent because it's a park board that can go anywhere and the Banana is pretty much 90% park if not more. If you want a RC board maybe the TRS BTX but not sure about that.
for sure ... people get so uptight about board designations.. strap it on and ride it to hell with what its " supposed " to do. Need some info to back that up ? Look at Ready from Absinthe films .. Blair Habenchts entire back country part is on a banana.. not a btx all mountain board but an actual skate banana. Jeremy Jones is one of the best at mixing back country pow lines and booters with urban handrails. His only board is his pro model in different sizes. Heike Sorsa films his parts both park booters, back country pow and urban stuff on a burton custom. Yes there are board generalizations but they are just that generalizations. Park boards are normally twin tip softies with centered stances but that doesnt mean you have to ride that to ride park. My advice for anyone is find a board that you like in flex, comfort, and stance and roll with it. I would venture to say that if you had a totally black board with no logos on it most folks couldnt pick a custom from an agent. ( thats a general statement and not a slam or endorsement of either of the previous mentioned boards )
my picks for my boards atm are a 156 skatebanana and a 154.5 riders choice. I do feel the rc has a tad less flex than the banana. i have not had any rome boards for myself so cant comment on them but im definitely happy with my mervin boards both in performance and construction.