whats your monitor resolution? spec wise both are pretty much the same. the difference is their factory clock speeds. Asus has slightly higher , base, boost clocks by default. but if you need to overclock msi is better. cus msi cooler is far more better than the asus, so you can push it better. and the warrantly. you get 3 years of warranty with the msi. 2years with asus. usually msi and gigabyte gpus are considerded the top performing and best overclocking brands cards. go check hardwarecanucks.com , overlcokers.com, linustechtips or any other proper hardware forum.
with that said, that card will not give you the best price to performance value. specially if you plan to run it on a 1080p display. IMO r9 270 would be a better buy.