Hi and welcome. Explorers, like any other vehicle has their strong points and weak points but I know I see an awful lot of 1st and 2nd gen. Explorers around where I live, on the road every day. The only problems I've had are the ones well documented on this web site with fixes and advice on how to deal with those issues quickly and inexpensively and they have all been repairs that I have been able to do by myself or with my 17yo son's help and just a handful of common tools.
Things to look out for:
4x4 shift motor
Radius Arm bushings
door hinge pins and bushings
broken inside door handles (caused by bad hinge-pin bushings)
Blower motor and resistor
Most of these have been normal wear items, not at all uncommon on a truck that is 16 years old with 150,000 plus miles (240k km.)