I fixed up my mother-in-law's 820, which looked identical to the one above, but in the 14.5" in size, and it weighed in right around 38 lbs. SUPER heavy. If you want the bike for XC (cross-country), you should be looking at a larger size. If you want it for free-ride/jumps/whatever you might consider a slightly smaller bike, but 13" still seems too small in any scenario...
It's not a good deal because those can be had new for only a bit more. And the judy is an upgrade, but not a huge one.