If you decide to go for the Christian Bands, you should look into Rock the Universe at Universal as well as Night of Joy at Disney. Unfortunately, they are held the exact same nights. A large number of the headlining band alternate between the 2 venues. When bands get set, I'd look at both parks and decide which has the bands I'd prefer listening to. Universal normally has great prices on their "rock your weekend" tickets that include tickets to the parks and tickets to the concerts. They are normally cheaper than tickets to the parks alone but they are dated for that weekend only.