Canary Audio CA-100 or BAT VK-300 for callistos?

You certainly made the right decision. I have had a few Canary amps before and I now own a pair of their CA-339. My Cousin also has a CA-100 and according to him, the Canary blown away the Cary V12R that he used to have. I agree that customer service is an important issue and Canary always provides timely response whenever I needed their assistance.

You should first try the stock tubes and see how you like them. If you really want to upgrade, then you should go for the EI 6CA7 or the Mullard EL34 but they are very hard to get.