I've had a really bad experience with MSI, so I personally would avoid them. They're customer service is okay, but the build quality of their cards can be awful, I'm going to have to RMA my R7870 HAWK a third time, because they just can't seem to get it right.
Sapphire's international customer support is supposedly awful. Outside of the US you apparently have to ship your card internationally, possibly across an ocean, and that will cost you a pretty penny to do so. I have owned one Sapphire card, and it hasn't failed on me yet, it's serving as my backup card for when my MSI card seems to inevitably fail .