The thing is, we probably have to buy a striker in the summer anyway, RVP is going to be 32, Hernandez will likely move on, so we will only really have Rooney as a prime striker. Who else is a world class striker that will available? Aguero? No, Lewandowski? Nope, Suarez might be available if he doesn't score much but I doubt we will even consider buying him, which leaves Falcao the only reasonable option, unless we move for a young striker with potential.
As it stands, I'd buy him as a RVP replacement in the summer but that doesn't hide the fact he has been shocking in some games so far, he can't seem to run properly and hasn't adapted to the English game yet. Then again it's likely already a done deal and Falcao is probably already a United player but then we should be looking to move RVP on in the summer.