Able was a top notch semi custom Maine builder, in the same neighborhood as Hinckley and Morris. When they went belly-up, Morris bought their manufacturing facility and is building from at least one of their hull molds. I would easily speak of Able in the same breath as Morris.
These were very expensive boats when built. Most were Chuck Paine designs, very similar to Morris's. Like any boat, the value today is entirely dependent on maintenance history. Which size are l you looking at?
I think the little 32' was one of the nicest I've seen that size. The 42' is lovely. The bigger 51' and 58' are real ocean voyagers. I looked pretty close at a 42' some years ago, there are only a few builders who can match that level of joinerwork. Morris would be happy to service one if you make a deal.
The later ones were cored hulls and decks. A good survey can let you know if there are any problems.