Back in January, FCA mailed me a coupon for $1000 off a new Jeep product and a $50 gift card for taking a test drive; so I drove a stick-shift JL. I really liked it. Of course, the JL was a new car - so no surprise that it was smoother and quieter. But a lot of things that we all added to our JKs are incorporated in the new model - e.g. - grab handles, aux. switches, better hinges...
The JL that I drove on a Michigan January day had a steering wheel heater! That almost made the sale. Also a large display for the radio/back-up camera (my JKU has the basic radio with no video). And the new doors are aluminum, so they are much lighter (and sheet metal repairs more expensive, no doubt) to remove. The new tail door is magnesium, and is shockingly easier to open & close (but then, that's compared to my AEV tire carrier. The windshield is more easily folded, and there are a few different roof options.
My '15 JKU has only 38,000 miles. I'm retired. Our daughter's wedding is pending. So, about the only way I'd add a JL to the stable is if I won the lotto. In the meantime, I like my Anvil JKU, but wish I'd ordered a Rubicon/stick shift. I'm hoping to make a local deal for a Rubicon front D44.