Gigabyte use more copper than other manufacturers. This is probably the reason that Gigabyte MBs are more reliable especially compared with MSI. Stick with asus, asrock and gigabyte MBs. Most others are problematic. MSI is famous for this as well as compatibility issues with memory and GPUs.
Both boards have the same 8-pin ATX 12V power connector and the usual 24-pin ATX main power connector too, so I'm not sure what you mean by different power phases here. Can you provide a link. I'd like to look at the info you are talking about.