The are pretty much equal boards in terms of features and quality. The one area where the Gigabyte probably outshines the MSI is in terms of reliability due to the lack of manufacturing defects found on MSI boards in higher than average numbers as compared to the other three big name board manufacturers. I see a lot more quality control issues, especially since the last two years, on MSI boards than ASUS, ASRock and Gigabyte, combined.
MSI got a lot better about quality control on their motherboards for a while there, but they've backslid the couple of generations. I have no qualms about their graphics cards, but due to the high numbers of problems due to defective boards I don't recommend them. If you are willing to roll the dice on the idea that YOUR board won't be one of the unlucky ones, then it's probably just as good as the Gigabyte. Personally, I'd go with the Gigabyte, or better still, an ASUS or ASRock board.
This board is probably a better choice than either of those, has better power phase design and is about the same price.
PCPartPicker part list /
Price breakdown by merchant
Motherboard: ASRock - X470 Master SLI/AC ATX AM4 Motherboard ($143.88 @ OutletPC)
Total: $143.88
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2018-11-02 18:20 EDT-0400