Well, I've had my 2020 for a couple of weeks now and thought I'd write a comparison on some things coming from someone who's actually owned different configurations now.
2019 was a JLUR with tan leather and the 4 cyl with eTorque.
2020 is a JLUR with aftermarket "Mopar" leather and 6 cyl.
I'll do the engine comparison first since that's a big topic I see discussed on here a lot.
The 4 cyl with eTorque had a lot more instant power available and honestly "drove" better, but was very buzzy/rattly and you always heard it working. Even with as horrible as it sounded, I was debating going with it again for 2020 because it drove so much better, but when they no longer offered it for the JLUR in 2020 (4 cyl available, but not with eTourqe), I decided to give the 6 cyl a try.
Even though the 6 cyl definitely doesn't have as much grunt and I'm getting 3-4 MPG worse than the 4 cyl, I honestly have to say I like the 6 cyl better overall. It still drives fine and is SO MUCH QUIETER than the 4 cyl. No more rattling/buzzing all the time. Just a slight growl and/or intake noise when you have to get on it.
In summary, the 4 cyl drives better, with better MPG, but I just couldn't stand the sound, so the quiet smoothness of the 6 cyl outweighs the extra torque of the 4 cyl. In my opinion anyway.
As for the interior option comparison, when you do the "Mopar" aftermarket leather (I did the black "stitched" leather), you essentially get reverted back to "cloth" interior and then they add the leather. This means you don't get the little bit of leather on the dash or on the ebrake handle, neither of which I even notice. However, you also lose the fold down armrest in the back seat and you end up with the dash panel in red instead of gray like when you choose the tan factory leather option. I don't sit in the back seat and the color of the dash isn't a big deal to me either. For a comparison of the actual leather seating surfaces, I have to say the aftermarket leather is MUCH nicer and even feel more comfortable. Maybe it's the "stitched' pattern, but in addition to the leather being softer, the seats actually feel like they have more padding. An odd thing I also noticed is that the interior door handle on my 2020 is smaller. I keep a pack of smokes and a lighter in the door handle hole and they fit with no issue in the 2019, but not in the 2020. I don't know if this was change across the board in 2020, or if it has to do with factory leather or not.
Finally, the lovely steering issues. My 2019 had sloppy steering with a big dead spot that caused it to wander, but there was death wobble. As I continued to drive it (about 12k miles), the steering got a little tighter, but the wobble was starting to show itself. I never took it in for any of the recalls because of mixed reviews, the fact that the closest dealership to me absolutely sucks, and that I knew my 2020 would be here soon. Well, the steering has NOT been fixed on the 2020. In fact, the wandering is WORSE than on my 2019. It's seriously spooky to drive. I don't know how they've had this issue since day one and still haven't fixed on the 2020's yet. We'll see if the 2020 follows the same path of less wander and more wobble as time goes on. Honestly, if the steering doesn't tighten up some, I'm going to have to take it in and have them start throwing parts at it because it's so bad. It's so bad, my wife won't even drive the thing as it is now.