It's easier to pick out the differences than to cite the similarities between the two vehicles. Up front, Mountaineer gets a flashy chrome waterfall grille emblazoned with a big round Mercury logo at center, a more refined look than the truck-like Explorer. Big headlights and a chromed bumper strip above body-colored panels complete the elegant look. Simple badging around the rest of the vehicle, along with a few pieces of shiny trim here and there, represent the only other big differences you'll find between Mountaineer and Explorer.
My test vehicle was equipped with optional ($695) power running boards that automatically folded down when the doors were opened. On a big SUV like the Lincoln Navigator, I love this feature. On a mid-size like Mountaineer, the running boards were a nuisance. At 6'2", I don't need help up into the driver's seat, and the running boards consistently hit the backs of my legs as I exited the vehicle. Drivers who are short of stature may appreciate this feature more than I did.
In the Driver's Seat
I guess this fits into the "if it's not broken, don't fix it" category of design and engineering. Mountaineer's seating is comfortable, firm and supportive, an especially good fit with broader expanses of human behind. Power adjustable foot pedals are a nice option ($225). I wish that the steering wheel adjusted for reach as well as tilt, but I didn't have a hard time finding a good driving position. My test vehicle was equipped with a $2,845 navigation/moonroof package that places a big LCD screen at the top center of the dash. Mercury's navigation software is one of my favorites, with clear instructions and a very intuitive interface. Despite the price, I'd tick that option box on my Mountaineer, and avoid the hassle of the aftermarket.
Second row seating is comfortable, with a simple two-tone split bench seat and two-tone door panels. Access to the third row is good, but space back there is tight -- better for kids and small adults than for full-sized humans. My test vehicle also came with an optional ($1,295) DVD rear seat entertainment unit, which I would skip -- for a lot less money you can get a portable unit for each rear seat passenger, and more harmony will reign. Or you could even -- gasp -- speak with your passengers on a long trip.
On the Road
It's hard to complain about Mountaineer's suspension. Each wheel is independent, with coil-over shocks and control short and long-arm architecture. There's a big 32-mm stabilizer bar up front, and a 25-mm unit out back. Combined with rack-and-pinion steering and four-wheel power disc anti-lock brakes, the suspension delivers a very comfortable, stable ride over most surfaces. A very tight 36.8' turning radius helps make Mountaineer one of the easiest mid-size SUVs to drive in a parking lot.
It's impossible to consider Mountaineer and Explorer without hearkening back to the rollover disasters of the 1990s. Mercury has equipped Mountaineer with a ton of safety feature to allay public fear, including standard traction control, a safety canopy system, dual stage front air bags and a tire pressure monitoring system. Mountaineer is still a big vehicle with a high center of gravity, but I'd feel confident driving one on a daily basis, maintaining an awareness of its handling and cornering limitations.
There are certainly other mid-size SUVs to consider. I love Toyota's 4Runner -- my daily driver, Moose, is a 1994 model. Nissan's Pathfinder has grown in my esteem over the years. Jeep's Grand Cherokee and Chevy's Trailblazer are both vehicles with lots of heritage and ability. If fuel economy is a concern, consider the next size down. A Mercury Mariner, Ford Escape or Toyota Highlander can do almost everything that a Mountaineer can, and you can choose a hybrid gas-electric powerplant to maximize your gas savings.
Forgive me if I don't get the tingles at the mention of a Mercury Mountaineer. I know that it's important for Lincoln Mercury dealers to have an SUV on their showroom floors. I just wish that there was more distinction in the vehicle, and more magic left in the Mercury name.