He has the charisma, and will probably do well with scripted promos. He's a subpar brawler, and only has two decent power moves, and one of those being the Alpha Bomb... which he can probably hit on someone no bigger than Helms or Michaels. Has a good enough look, and is totally different than Lashley. Brown plays a great fun babyface, while Lashley can play a monster face or heel.
It all depends on what WWE wants to do with the guy. I'd like him on Smackdown, but that wouldn't work out too well. Smackdown is hurting for depth, but I can't see him doing anything on there. He'd be fine on RAW. He could be new ECW's first big over the top personality, but I couldn't see him doing well on the show. I don't think he, nor anyone else could work as the free agent gimmick I wish WWE would run with for a few months... which would be someone interacting with people on every brand, squashing jobber, and cutting promos before making his big choice
at a major PPV.
I say Monty lasts 2 and a half years. He'll get over, but will quickly get exposed by someone higher up.