I just brought a JK 4 dr Rubicon to replace my aging GQ Dual Cab, and I cn't comment on it's offroad ability yet other then it seems to have all the right gear and has awesome low gearing on some crossed up grass ditch work, I've tried. The engine seems to lack bottom end torque a bit but other users tell me it's just running in.
I originally put my deposit on a 4 dr hard top standard with the adventure pack steel bumpers/sliders, but after doing my homework decided to spend the extra to upgrade to the Rubicon.
Differences between the basic Jeep and Rubicon.
I sacrificed the Hardtop to afford the upgrade, was going to add it afterwards but it was going to cost $5200 to add. and there are aftermarkets ones from around $3500, and visibility is better in the softtop even with the top on. The Rubicons seem to come as softtops from factory so don't have rear washer/wiper/demister switches.
I gained front & rear lockers and swaybar disconnects, a Dana 44 front diff instead of Dana30, 4.10:1 diff ratios instead of 3.21:1, 4.00:1 low range ratio instead of 2.72:1. So the crawl ratio is 73.1:1 instead of 38.9:1.
I added the Adventure Pack which gave me solid steel bumpers front & rear, extra bash plates underneath and double rail rock sliders better than the standard Rubicon. And the good thing is all this stuff is factory so no voiding warranty. And it's cheaper than aftermarket anyway when you price it all.
And adding an aftermarket hardtop isn't going to cause warranty issues. The soft top is nice, tight and quiet, no flapping at 120kph.
They have potential to be very capable, you can fit tube/checker plate doors and fenders when you want to play and swap back to the nice ones later. They are only limited by your fear of warranty issues and credit card payments
Oh, check
http://www.ausjeepoffroad.com, there was a red Rubicon 4door in WA similar specs for sale for $35k, worth the plane ticket in my view if I had seen it earlier.