Doc X,
From what I have seen, you will not have any issues as long as you religiously check your oil level. I check my oil at every fill-up. I rarely, if ever, have to add any. But, a sudden decrease in the oil level is the first sign of a problem. My beast now has 65K miles, and I have not had any problems. Right now, price considered, there is not any other vehicle that I would rather be driving. These things are a blast, and people never stop asking you about them.
There are replacement engines if you should need one. My bet is that you won't as long as you follow the guidelines above.
As far as which year to buy, I would try and find an '00 or '01. I held out because of the 18" wheels/tires and the automatic climate control system (a feature that I now won't be able to live without). If you can find one that was taken care of, I promise you will be happy. One other note: these are probably not a good vehicle if you often haul around more than one other adult, or if you have kids in child seats. My friends and family are well aware that is a pain in the *ss to get in/out of the back seats. They alos do not have a large amount of cargo space, but that is why I have a utility trailer.

Hope this helps.