Both systems have the follwoing same components:
Intel® Core™ i7-4700HQ 2.4 - 3.4GHz, Intel® HM87, 17.3" Full HD Matte LED, NVIDIA® GeForce® GTX 770M 3GB, Windows 8 64-bit
with the following component differences:
MSI
24GB DDR3, 2x 128GB SSD + 1TB HDD, BD Burner
ASUS
16GB DDR3, 256GB SSD + 1TB HDD, DWD±RW
ASUS will probably be much quieter and run cooler. MSI has some extra ram but its unnecessary and wolnt help on the performance much. They have the same exact screen so if you are scared of the issues that some of the ASUS screens are having the MSI is just as likely to have them.
ASUS G750JX
CPU: Intel Quad Core I7-4700HQ @ 3.4GHz
GPU: Nvidia GeForce GTX 770M @ 932Mhz
RAM: 16GB
Memory: 1TB + 256GB SSD
OS: Windows 8