Nice choice! Buying stuff used is almost as good as borrowing. You can usually get out with minimal cost. If you choose wisely your education value is worth the small loss per trade. Moscode used to offer trade in of 300/600s towards new amps. The current 402Au is a gem, one of my fav amps.
Rich,
I have had a Moscode 600 for 26 years now and have to say that it is a real overperformer. Incredible bang for the buck. and very reliable. I had it upgraded by George Kaye and have to say that while it is note as good as the 402 (I haven't heard the Au version yet), it is dam close and can be had for 1/10th the price. My son is now using it in the mini-mancave and after all these years it is a rock solid as ever. I would still be using it myself had I not been made an offer I couldn't refuse on the Vt-200. (nad oh, by the way, I could buy two Moscode 600s for what it cost me to replace the output tubs alone on the ARC
)