The 2008 X in my signature has 390,000 miles on it. Most reliable vehicle i have ever owned by a wide margin. Better even that the drivetrain held up, all the ancillary stuff holds up pretty well also, meaning its not perfect but its not a rattling mess either.
The early models had some issues, so if you go to Nissan sites they will tell you about SMOD and timing chains and 2 gear spider setups. ALL of those were fixed by Nissan by 2011. The 2011 Frontier in my signature - almost identical drivetrain, has 158,000 miles on it and has literally needed zero. I changed all the hoses and front wheel bearings and U joints at 100K just because -all the ones coming off actually looked fine.
One thing I will say is mine have never seen salt, and I don't think Nissan's are the best for dealing with salt, if the message boards are to be believed.