I've used both the Asrock and the Asus board, both solid boards that overclock within MHz of each other.
The Asus is absolutely not worth the premium over the Asrock.
The Asrock is one of the fastest booting boards I've ever used when paired with a fast ssd.
It's only negative is the socket placement for the Larger air coolers, going custom water or closed loop such as H60 etc makes this a non-issue.
The M-sata connector on the back of the board 'may' require you to trim certain backplates.
Your current A70 will block the pci-e slot, rendering it unusable on the Asrock board.
If you do go custom water, go EK Supremacy, get the EK TRUE 1155 backplate and the Easy mount kit.
Custom water is a pile to spend on an M-itx build, a relatively cheap (by comparison) H60 will keep that 3570k quite happily at 4.6GHZ with 1 almost silent fan.
The Corsair backplate just misses the m-sata connector and does not require trimming.
The Gigabyte has no vcore adjustment, no good for what you want it for.