They are both nice, yet if I were you, I certainly look at MSI GT72s for its gaming features in several ways, such as cooler boost 3, MXM design, dual NVMe SSD and Sabre Hifi. Especially for its thermal design that dissipate heat swiftly by dual-fan with above 5 heat pipes embedded in the machine. GT72s is powerful.
Nothing like rushing to pick the best answer when only one answer has been posted and the original post has only been up less than one hour. When people see the question has already been "solved", they don't bother reading and then posting their opinions (for the most part). Try a little more patience next time. Just a little food for thought.
FWIW, I would have gone with the MSI. Never liked the rubbery finish on the keyboard deck/palmrest of some of the ASUS G-series (I had a G75). The performance of the MSI is the equal of the ASUS, and the redesigned GT72 has an excellent cooling system (much like the ASUS), compared to the earlier GT70 models. The MSI also has the superior keyboard, and the speakers are probably better.