ASRock is more popular than MSI.... 1. Asus 2. Gigabyte 3. ASRock 4. MSI That's their order for sales.... ASRock is #3 in the world in sales. They passed MSI last year.
Although you may be able to gain a high OC on the Pro3, it may not be able to hold it for as long a time as higher end boards. This is due to fewer power phases which means more load on each phase causing them to wear out sooner.
Thats true. If you want to hold a 4.7ghz OC 24/7, better go with the extreme4. Although I think its less of an issue with todays lower TDP CPUs than those back in the day, ie, Nehalem.