Choosing between any of these bikes, you'd be best to know what you were going to be doing with the bike. If you do a bit of everything, like I tend to do, then they all work but two better than the others. I'm personally torn between the Honda and the KTM. I lean towards the Honda for it's new light feel and agility, plus a motor that is snappy and responsive while still being friendly when it needs to be. Even on the MX track, the X was surprisingly good. It runs like that straight from the dealer and in the hundreds of hours I've put on CRFXs I've never had a mechanical issue. But I don't hit the rev limiter or let my bikes suck dirt past the air filter either. I'd definitely have to get a bigger tank and I wish for the 6-speed of the KTM out in the desert.
The KTM would be a solid choice mostly because it will do everything well and suffers very little no matter where you are riding or racing, with the exception of the MX track and KTM makes the XC for that. The power is buttery smooth and then it really comes alive up in the spread, it is clearly the fastest bike here. I'll bet these motors will run forever and I know the chassis stays tight for a long time. I miss the lights and I think the muffler could be a little quieter, but those are small issues easily fixed.
Between these two bikes it comes down to how much track time I'm planning on putting in. More track time means the more I prefer the Honda.
If I were just trail riding I'd seriously consider the Kawasaki. It feels fast and is friendly, and so quiet! It has the plushest suspension for the more relaxed pace and you can sit down and have a blast, not a sore ass. And the WR is definitely at home if you are riding faster and more open terrain. I was surprised at how many of our testers liked this bike so much on our desert ride. Just know that you have to fiddle with it a bit to get the bike running up to par.
Jimmy Lewis 5'10"/185 lb A Rider