Robinhood is iOS only, they don't offer ANY other method of trading, plus you have to join a waiting list for an account. Personally, the lack of a backup option would be a big turnoff if I was trading single stocks anyway.
Unless you have a lot of different stocks, you're probably better off just selling your Scottrade stocks and then consolidating with Fidelity. That said, don't forget that this move would be a taxable event.