I agree with the TAD-60 since it is so versatile. It allows you to hear a variety of tubes, it has on the fly feedback and on the fly switching between UL and triode modes. It can also be used as an amp or a single input integrated. I learned a lot about tube amps by owning one of these.
Looking for a first Tube Amp for under $1000
What would you turn to? I've read some very positive comments on the Onix SP3, Jolida JD-502b and the ASL AQ1003DT. What would be a good first amp which is easy to use (setting bias)? I mainly listen to rock and jazz and the amp would originally be played through a pair of Bose 301-IV speakers.