If you're committed to a full AMD build, if you can grab an MSI R290 for under 400 bucks, that'd be a good call. Usually they hover around $450 but you know how these things work. Next week they could be $380.
Definitely grab an MSI make if you can, according to reviews, they're much more receptive to OC, run cooler and are generally more stable than Sapphire or Asus.