Hey Craig...
Welcome to the board.
Now as to your questions:
1. Is The VX worth getting? My answer would have to be; not only YES, but HELL YES. I finally bought mine after an almost two year search and love every second of it. I too bought mine as a "Collector's type investment" because of the looks, reputation and their rarity.
2. What's a good price? Well I have seen them go for as little as 11K and go all the way to about 17K. Not bad considering the original 30K sticker price.
3. What's the best year? All three years are the same. The only major difference is the '00 and '01 went to 18" tires/wheels and offered more of a color variety. Other than that all the years are the same with the same features.
4. What to watch for? As with any "used car" watch for the normal basics. One major trouble point on the VX are the power windows which have a tendency to get out of place when going up. If the dealer won't fix them under warranty then there are many postings here to show you quick, easy fixes.
5. Rough Ride? Yes, the ride is a little roughter than your average Rolls-Royce but he...who cares, it's a VehiCROSS. The car was designed to go off-road but it has great handling and super looks.

As I said earlier, I purchased mine as a pure investment but I love driving it. I have taken the car to many car shows in the past two years and I love the expressions from the people who see the car for the first time. Consider that Isuzu only produced 4,803 VX models between 1997-2001. If and when you find one....GRAB IT
Good Luck.....John