I think Florian is quite a common boys name in Germany but maybe sounds a bit effeminate to my British ear - however don't think it is awful and people would probably get used to it. However, I think it may take quite a confident child to carry it off.
Dorian just makes me think of Dorian Gray and Birds of a Feather, neither good. Would also seem a bit try hard.
I know an adult Dorian and he's as mad as a box of frogs, but great fun and very intelligent. Birds of a Feather has never occurred to me - and I used to love it - so I think you might be safe, there. I wouldn't name a girl Dorian, though!
I seem to recall an uncle Florian in the Chalet School books, but haven't cone across it anywhere else.
I like either name, though perhaps Florian is more open to unfortunate nicknames.