MSI is pretty good, one of the best of course, but "best" is more of a preference when choosing GPUs, to me best is when you have heard of the company yourself like it is well known. Then look and research about their customer service and see if they're good, they can have the highest clock GPU out there but if it doesn't have a reasonable warranty period and doesn't have good reputation for customer service, you'll be all left alone when you need help from them. So it really depends on those kind of things when you are choosing GPUs rather than just choosing the one that has the best stats. But anyways, MSI's Twin Frozr is suppose to have some pretty high clocks with really good cooling, Gigabyte is also great with high clocks and keep it's cool. So if you were going for the 970s or 980s, those two would be your best choice.
https://pcpartpicker.com/part/gigabyte-video-card-gvn970g1gaming4gd
https://pcpartpicker.com/part/msi-video-card-gtx970gaming4g
But I can't exactly answer your questions about OC since I don't OC a lot, so I can't help with that area. As that review has said, a solid 50+ fps is what you'll get if you go with triple 1080p monitors, so right now the only problem I see is to learn how to OC and you should be able to get 60+. So if you want to save yourself some money, go with the 970s and all you got to do is learn how to OC them, shouldn't be that hard. Or if money is not an issue, go with the 980s and you should be able to get 60+ fps with no problems.