The first generation Mountaineer was made from 1997 until 2001. It was almost identical to the Ford Explorer, but the base engine was a stronger Windsor V8 making 210 horsepower. The first year model did not sell well, so the Mercury design team went to the drawing board and made several changes to make it look different than the Explorer. The second year model in 1998 reflected these changes. The base engine was also a less powerful 205 horsepower Cologne V6, but with a 1 liter drop in engine size and only 5 horsepower drop in power, the vehicle was just as fast if not faster than its predecessor.
There was some controversy with these cars when it was discovered that there were a high number of rollover fatalities caused by tire blowouts. Ford/Mercury blamed Firestone, and the class action lawsuit was settled out of court. It was later determined that the tires and high center of gravity were only a small part of the problem. The major cause was idiot drivers who panicked after tire blowouts and hit the brakes and jerked the wheel at the same time, causing a rollover. I've seen someone do this with a low center of gravity Dodge Stealth, so I'm confident that the conclusion that driver error was the cause of these fatalities is correct.
The second generation of the Mountaineer lasted from 2002 until 2005. It had more luxury features to make it different than the Explorer, including rear TV/DVD player for entertaining the kids. The SUV was refreshed in 2006, the third generation of the vehicle.
The design is almost the same as the 2005 model, but the frame is completely new.
The Mountaineer has one of the highest owner loyalty ratings of any SUV. People who buy them tend to trade them in for a newer model every few years.
With so many of these vehicles traded in for newer models, there are a lot of them out there on the used car market. You can find some great deals on these SUVs if you know where to look. I would check out eBay before going anywhere else.