A friend of mine who reconditions tape machines is a big fan of Otari machines. He said they are easy to service and are built like tanks so they are quite durable. The downside is that most were used by professionals, so they have been subjected to very heavy use. Another friend bought something like ten machines from a folded books on tape operation. He got all of the machines, plus other gear for a few hundred dollars and has been slowly selling off machines and parts.
Not that long ago, I got to hear a big Studer that sounded really good. It is one of those holy grail machines, along with the Ampex ATR 100 machines (I've never heard one) that the very serious tape fans seek out. This looks like a fun hobby for those who are not as lazy as I am--I don't play my turntable that much because of the extra effort required over using a music server.

