I like wasting electrons.
The interior is not as plush as the 3's, no question about that. I found the ride comparable to the 3.
There's MORE rear seat room in the JK. More headroom, legroom and hiproom. What may be throwing you off is the back of the rear seat. It's angle is more verticle then on the 3 and thus, IMO, not as comfortable as the 3.
Front and rear lockers, unbelievable approach and departure angles, more clearance, longer wheelbase... The JK is the best "out of the box" 4x4 on the market. It's not the best 4x4 to take on trips and to the mall. It's not nearly comfortable enough.
I've said it before, the JK will outperform the 3 and 2 stock vs stock. That's just the way it is. And a lifted JK is going to kill a similarly prepped 2/3.
But yeah, it's not as plush and comfy.