What do you mean? They are both gtx 760s so they have the same specs apart from the cooler and on some models a factory over clock which means nothing since you can do that yourself
The Gigabyte (Windforce model) has the better cooler, but is also extremely long. If it can fit in your PC's case, I'd go with Gigabyte otherwise (if they are the same price), MSI is the best choice.
They run at about the same temps and about the same noise. The msi is a little smaller and looks a lot better IMO. I'm not a gigabyte fan and I like msi so for me the choice is easy
What do you mean? They are both gtx 760s so they have the same specs apart from the cooler and on some models a factory over clock which means nothing since you can do that yourself