Got this truck in college, and I've driven it for 155,000 miles. I won't get rid of it. In all that time, I've just changed brakes, oil, radiator fluid etc. I've only had a problem with the Mass Air Flow sensor ($400 for a new one). Aside from that, never had a reliability problem. The only hassle with this truck is that it requires a somewhat obscure GL4 transmission fluid. I've never been able to buy it in stores, so I use GL5.
Best feature? How about a cheap, durable, and reliable. Not having a payment, and not having to constantly sink money into it is a very nice feature.
You can buy a used CD player from an older Xterra as a bolt-in replacement for the stock CD player. No need to mess with the harness. You just lose that little "stuff pocket" under the old stereo.