As it stands I think the final will be between Amelia and Marcus/Craig, cant split them in terms of their public perception. Things can change very fast though, I believe Janet is 1 outstanding performance away from being the one to beat again to be honest. Fans are very fickle, if she survives this week and gets high praise from the judges next week, people will latch back onto her.
So ultimately, seems Im a Janet fan I do believe she'll turn it around and get to the final in a face off with Craig.