I don't think there are really good years and bad years so much as there are changing neck profiles.
There is the try before you buy thing, but then again, Ricks also hold their value really well, so if you get one and don't like the neck profile on it, you can probably easily flip it for the same price and try again.
Ebay is pretty hit or miss, really. Lots of people are paying a bit much for them there.
Older ones might be cooler, have more mojo or whatever, but the newest ones do have some features that the older ones don't. Basses made in the last couple decades will have easier to adjust truss rods, and in the last few years they've added adjustable pole pieces on the pickups, and the vintage push/pull tone circuit so you can have the option of either the older sound or the newer one.
Still, you can often find old ones, specially 80's ones, for decent prices.
For the same amount of money, unless it's a really really old one, I'd prefer one from the last few years, honestly.
Oh, as someone else mentioned, there's also the 4004 model, which is very cool. Some people might prefer it for the humbucking pickups and the contoured body.