The 300b is my favorite tube but I really like the extension of the 2a3/45. My wish came true (I didn't know I had one) when I got a high eff/easy load speaker with an active x/o. I run a 300b on the mid/woofer and a 2a3 on the tweeter. I initially ran a 300bxls on the low and 300b on top and it was nice but the 2a3 on top is noticably better.
The 845 is my fav high power SET tube.
The 845 is my fav high power SET tube.