Your gonna NEEED larger tires to off-road with an XL7. The stock 235/60's are way too small. But 225/70's fit perfectly and add a touch over an inch in clearance.
Front articulation sucks, but as with most IFS rigs it's on par.
Reliability... PAH! You own a Jeep, it's nothing like that. Your original tranny will still be in the truck after 150k miles, and you won't be replacing DI's every 3 years or Master Cyl's every 4. I have a Jeep too, had several, before that had Suzuki's... The Suzuki's are far more reliable than most, and I'll include Toyota in there as well (have owned several toyota's and currently own 1 Lexus). The Frontier is a decent truck as a truck and depending on your setup would be better to take off-road than an XL7. But an XL7 has major potential. Downside is the lo-range being 1.82:1 but with an automatic and 5.12's in the diffs it's not too bad.