Keith (formerly owner of Mongoose Machine) has one. He likes it.
I bought his used freeride 350 four stroke. I took a look a his xtrainer, did not ride it though. Beacuse it is shorter, a bit lighter and has mellow power delivery, most ride reports say it would be good for new enduro riders, shorter riders, girls, or guys wanting a more mellow power delivery. Suspension is soft.
If you are on KTM talk, check the near last posting of this thread for a comparison of the FR250 to the Xtrainer.
http://ktmtalk.com/showthread.php?513484-Thoughts-on-Freeride-VS-Beta-X-Trainer
I had an FR250 since November. I wanted a technical woods bike for occasional racing and technical trail riding. Trials bikes were just too small, soft and the transmission a PIA. The 350 EXCF was good but tiring pushing it through all those tough trails at Tansky at race pace. The FR250 was a perfect balance, but I did not like the power delivery. After 6 months, I was going to sell the FR250 for the Xtrainer, but I really liked the ergos and geometrey of the FR250. I just wanted a different engine. Thats when I found out Keith had an Xtrainer and was selling his FR350. The FR350 is a perfect bike for be for my technical woods riding.
In the process I called the beta distributor out east. The xtrainers are in high demand (of course he would say that). Supposedly a few more 2016s coming later this fall, but most are pre-sold. If you are really interested, call the distributor, he will know if there are any around that you can look at.