I agree The Collective only ones who can make it. This format isn't the right platform for Bella, she will go the Matt Corby Lisa Mitchell route (former idol contestants) go away for awhile then come back in a indie Triple J style and distance herself from anything to do with Xfactor in my opinion anyway, she is great when she is good, but trying to make her mainstream to fit with themes of the show is ruining her.
Samantha Jade is good, but I dont see a big market for her here unfortunately, pop diva's dont really work here, Kylie holds the crown and has a tight grip, there are others, like Ricki Lee but even look at her, they just dont do so well here, I think she could do well as a early Delta ballad type artist, look at her first album it blew up, now she is trying to be pop, it doesn't work. Sam has the power in her voice, don't try and push her into a dance-esque singer.
Jason seems like a nice guy but he will be forgotten in a week, doesnt have a good enough voice to do to much, I honestly can see him doing the country club rounds for years but not much more.