HD 7970 + R9 280X crossfire, or one 290/290x

[Spartamk]

So the title basically raps it up, I have one monitor 1080p 60hz, I am not sure will the crossfire be bad because I've read there are a lot of stuttering. But is this the case now, I guess it's fixed now with 13.8 beta. Or one graphic, which will give me more frames to play on ultra settings? Thank you