Apple Ipad Mini Worth Buying or Waiting?

Hey everyone. I want to buy an iPad Mini for my fiancee but not sure if its worth waiting until the refresh or just buying one now. My only concern is if its going to still run well 2 years later after iOS 7 comes out. In short, my main concern is that iOS 8 is going to come out and just make it run like crap. Like iOS 6 did to my phone. Anyways, input is very much appreciated. Thank you=)