This. I can't remember what year it changed, but the first couple years the trans cooler and radiator were on a single core divided....that was later changed to 2 separate cores to avoid the "pink milk shake of death" when parts of the cores corroded and the fluids mixed. Other than that, nothing in particular stands out. Just standard "used vehicle" stuff to watch for. Opt for the Nismo/Pro-4x model with the rear diff locker.
Some people will be quick to chime in about a weakness in the front diff, but I have yet to actually meet anyone that blew their diff. Its always the story about someone that someone knows on the xterra forum type vague statements. Not saying it hasnt happened, i just dont think its as common a problem as some internet hype types would have it seem. The complaint was centered around a diff failure as the front wheel came down spinning and got traction and then broke. Sounded a little to me like that particular driver had a drive line failure of some sort on their way no matter what vehicle they owned......
I refer to my Xterra as my "reliable discovery 2"...kinda what it felt like to me. We've enjoyed ours quite a bit. There was an interior styling update sometime between 2010 and 2012 iirc, also....