My primary need is for playing back home videos from 1984-1995 on various grades of tape in any of SLP-SP modes. I read the AG-1980P is the one I would want for that.
I don't know exactly what I would like to pay. If I buy one on ebay I would probably have to spend about 300 on the core, $60 or so on caps, hope there isn't any mechanical damage, and then a weekend to put it together. I saw a TGrant unit sold earlier this year for $600. I'd love to pay that much for a unit like that.
I'm also interested in a TBC, such as the TBC-1000, and why they are used with a AG-1980 when it already has one inside.