Those are much better motherboards though. Brand name ones that are more stable and have more features. You'd be best off spending a bit more on it anyway, the motherboard is the center of the computer. You don't want to skimp on it.
I can guarantee you that the motherboards listed are top notch. They have many features that aren't supported in a mATX board. And also a lot more expansion slots that cost more money to run circuitry to them. i don't think you will find the same kind of flexibility in a mATX board. I would only choose a mATX board for HTPCs. Other than that you should go with a ATX board.