I bought this truck with 135,000 miles on it and it now has over 220,000. It is still going strong and is completely reliable. Mine has the 5- speed manual. Besides normal maintenance items (brakes, clutch, tires, etc.) I have had to replace both cylinder heads (they cracked - a very common known defect in this particular Ford engine) and the A/C condenser ($450). Besides that, no other repairs. I have off-roaded it many times and it has always done well. It doesn't have much pickup off the line at all. Mileage is crappy, at 14 city/20 hwy. With the new heads, it does not use a drop of oil, which is unusual at this mileage, so the bottom end of the engine is bulletproof.
I know raves about a 91 might not seem relevant to newer model purchasers, but I wanted to weigh in on the quality of Ford trucks. My family has never owned another brand. I'm the original owner of this Explorer, it has over 210,000 (hard) miles on it, and the alternator -- which went out last winter -- is the only major thing I've ever had to replace/fix on it. The power windows are starting to malfunction, but the ac/heater works fine, so I compensate. I want a new car, because I'm starting to hesitate to take this one on long road trips (still 4x in it though), but feel duty bound to run it into the ground first. I might actually cry when I have to let it go.
I am one of those that will truly mourn the day I have to get rid of my Explorer (though my wife will not). I love the styling. I still love driving it. Perfect size in my opinion. When we drive into Boston, we prefer to take it due to relatively small size, curb hoping ability, age, and slow speed manueverability. I used to do a lot of off road and beach driving with it. Sure, it's had its issues. Only 1 transmission rebuild in 320k miles. Original AC compressor is shot, fan motor is intermittent, 2 power windows dead. All in all, better then I would expect a car with 18 years and 320k miles would do. I have newer and 'nicer' cars, but this is still my favorite to drive everyday.
I purchased my Explorer from my girlfriend's father who bought it right out of the factory in April of '91. It only has 105,335 miles on it because he always telecommutes, but is truly a beautiful vehicle.
I bought my Explorer from a friend to have a vehicle to use for hauling, camping, etc. I now drive it all the time, I am almost at the 250k and this thing is still going strong, I did have a radiator leak, and had to replace the condenser, but I will drive this thing forever. I am a woman that likes new stuff, but I will cry when I have to give this one up.