I have a friend with one and it's pretty cool. Really zippy especially off the line. I am somewhat disappointed that it isn't faster like an electric motor should be though. I can't say that I'm super impressed with how little range you get when running full electric either and total range doesn't seem that great either. Also, all the extra weight from the batteries and the size of it under the Jeep isn't something I'm feeling. Overall, I think it's a neat idea but not enough for me to want.
One thing that is sort of interesting is the $7,500 tax deduction you get for the plug in hybrid. Also, the 4xe, Gladiator Rubicon and the 392 are the first Jeeps I know of that are over 6,000 GVWR which has some real tax advantages if you are self employed. Those might drive some additional sales.
I'm curious if the mods for the 4xe will be different than those for the regular JL. I could see the weight requiring some changes to suspension mods. I see that Jeep has it's own 2" lift (made by ???) which I assume will still allow for 35s comfortably.
Now if I can just get past the Max Care warranty coverage that I'd be losing on my 2008. That has basically rebuilt my Jeep over the years for $100 a visit to the dealer. Chrysler learned it's lesson and got rid of that and having a 4xe without that protection makes me a little nervous.