I purchased my Nissan Frontier crew cab 4wd in Feb of 2000. I still have the truck with just shy of 80k miles on it and it is still going strong. It has not required any major or even minor mechanical work aside from the usual things like new brake pads, filters and tires. All in all this is the absolute best vehicle I have ever purchased for reliability and functionality. This is the first time for me as a car owner where I am certain that when my current Frontier eventually fails I will happily buy another one just like it. :)
The reliability of this truck is just amazing. No repairs needed aside from standard use maintenance.
It is somewhat difficult for some folks to get in and out of the back seat. I would recommend slightly increasing the length of the truck to give the back doors a slightly wider opening.