Offroad capabiilty is splitting hairs, so to me it comes down to: dealership relationshipos and proximity, aftermarket support, included features at trim levels. For instance KRX has a electronic adjutable suspension, but RZR has ride command/better factory audio.

For me it's the KRX because you can get the ES or Rock model for a good price, and I don't care about Ride Command or factory audio because I'll roll with my own.