The 4th gens aren't too bad. I really don't care for the 5th gens too much. Seem a little too Honda Ridgeline-esque for my tastes.
I got the 3rd gen because I had a 4x2 2004 F150 and wanted a vehicle that was 4x4, just as reliable and perhaps with better mileage. So far I think I made a good choice.
My dad has wanted a 4Runner as long as I can remember, his dream rig is a older (80-90's) landcruiser. He has a 99 Chevy 4x4, but wanted something with 4x4 but a more comfortable rig to go up to the snow and short road trips (200-300 miles). I think he made a good choice too. My mom loves it (which is also a plus for him).