Well here is how I see it:
The guys might just cancel each other out, leaving Carrie and Taylor to battle it out.
There are alot of pop voters that have never even heard of Jason Aldean, sadly-- so that could hurt him at the Grammys. Lady A beat Miranda last year at the Grammys based on pop crossover success...so the Grammys are becoming more of a popularity thing now then merit, sadly.
Taylor might win on name recognition--- but-- Carrie has name recognition too. So this could be close.
What could be a deciding factor is how sick are people of Taylor winning? Alot of people are dang sick of her, and sick of her fake face when she wins. Also, after her terrible Grammy performance, who knows if the voters are as keen to pick her. There is no Kanye West sympathy vote to help Taylor win this time either. So that could be a factor.
I still think Jason Aldean is the favorite in the category---- but he lacks the name recognition of Carrie and Taylor among pop voters.
Final prediction: too close to call