Well I'll update my status: Still have the X. It has 191,239 miles on it. Had the valve cover gaskets and the oil pressure sending unit replaced last year, the drivers side lower control arm and torsion bar replaced the year before along with the high pressure AC line and early this year the distributor went out on a trip to Columbus, OH. Other than that she is doing fine.

I too am shopping for a Pro4X but have been reading they now use the R180 from the 4 cylinder as the front diff instead of the R200A in the old X and folks are having failures left and right? Also that the rear diff is now a M226 instead of the bullet proof H233B in the Gen I Xterra. In 2008 Nissan added a second set of spider gears to the rear diff to improve it's strength so it should be OK now. I'm eyeing a 2011 PRO4X with 44k on it. I will probably keep the 2000 X for another year or so...