I bought this as a third vehicle (instead of a work truck for my rental properties) with about 160k miles. I have owned it for a little over a year and it just hit 170k miles with no major problems. The original owner maintained it well for it's first 160k miles, as have I for the last 10k miles. I do have to replace the power steering pump soon, the loud whine that seems to be a common problem, but otherwise no problems. I have never owned a car with mileage this high so I have no basis for comparison but I am very happy with the reliability.
It also drives great and if the odometer said 50k miles I would believe it. The navigation system seems very modern for a 12 year old car and the leather is in like new condition. We have an Infiniti JX35 with 50k miles and the drivers seat is already more worn than this MDX with 170k miles; they must have used a very high quality/durable leather.
The only downsides are no blue tooth in the 2004, I believe 2005 models have blue tooth, and the interior is small for a 3 row SUV (trade off for handling well for a 3 row SUV).
Overall this is a great car, got it back in 2004 brand new, traded up from the Maxima, MDX handles excellently in bad weather, awesome traction. Great room in the back for the kids. I have 90,000 and it started requiring maintenance, so far replaced 2 engine mounts and will be replacing the 3rd one very soon along with the inner tie rod, the rear shocks had to be replaced at 30k. Funny enough I don't do any off road driving or towing, just regular city commute. We'll still keep the car for another 10k and probably trade it for something else.
Love the roomy interior, good quality materials, great traction-in snow, nice stereo
Improve the mpg, at 90k I am only getting 14.9 mpg