Which Motherboard is better ?

They seem similar in specs, though I usually lean towards ASUS for quality of the hardware and software.

Having said that, MSI has been improving and a QUICK look suggest the MSI board might be the better value.

MSI review-> https://www.techpowerup.com/reviews/MSI/Z170A_GAMING_PRO/14.html

Asus review-> http://www.kitguru.net/components/ryan-martin/asus-z170-pro-gaming-motherboard-review/12/

I suggest trying to find as many links as you can.

If you compare at NEWEGG and other online stores then make sure you compare the average customer rating at the same store, and not NEWEGG for one board, and NCIX for a different board. They are oddly sometimes much different (i.e. 3/5 one store and 4.5/5 another). You'd think they would average out.