I assume you're referring to 4wd buggies here? I'd say you have three realistic options - CAT 2000/EC, Lazer ZX/ZXR, and YZ10.
For the YZ10, I just ran my 870C at the Vintage Nationals in Bethel, CT, and it did very well (video link:
http://www.youtube.com/watch?v=w9jBQuxy9xQ). I love my 870C - it's an animal! It is technically not as "great" as the '94, but it's easier to find (and easier to find parts for), and can be set up to drive quite well. I also have a '94 runner, but I tend to restrict that only to "clean" tracks which do not have many loose rocks, since the 33T pulleys are much harder to find than the 35T pulleys. It is not hard to fab a rear dirt cover out of lexan, though, and I do very much enjoy driving it. Takes a bit of time to get used to the center one-way, though, especially if you're on loose dirt.
The Lazer ZX/ZXR is arguably more competent than the 870C, but it is a total pain in the butt to get to the gearboxes and replace belts/pulleys. I have one as a project car and may run it a few times, but I honestly don't take it too seriously, as working on it is way too complex for what I think is a relatively simple design. Spare parts are also difficult to find and people tend to sell them at extortionate prices.
If you can get your hands on a CAT 2000/EC, that thing is a beast. Plenty of suspension travel and probably way better over jumps than any YZ10. I have a CAT 2000 that I plan on running soon, and I expect it to be much more competent where I race (U.S. Northeast). It is comparably easy to work on as the YZ10, but has way more tuning options. Spare parts are also not too hard to find.