I'd go with the Giga. Giga has a history of building some of the most robust boards ever. MSI, notsomuch.
DQ6 comes to mind, one of the most solid boards ever made, period. I've had the pleasure of owning many of them.
Have seen MSI boards blow up. (more than 3x) To be fair, I did catch an EP45T-USB3p vrm on fire, maybe it's just me..
It didn't like 2.1v
vrm flared up like a match head. Yeah, this session's done.
It did take 2+v to make that happen, though.
Okay, in all objectivity: Compare the chokes on the 2 boards and see which has higher quality and quantity.
I have a feeling Giga will be better. Ofc then there's BIOS implementation..Giga is OK there.
IMO, Asus and AsRock are better BIOS-wise.