300B king of tubes?

Ryllau- I have the 805c amps. I replaced the Kron with the WE and found a subtle but clearly audible increase in sweetness and delicacy. The Kron is a very good tube in terms of frequency extension, but it does have a rather direct presentation in comparison to the WE. Is it worth the cost difference? That's obviously dependent upon the level of the rest of your system and your personal preference. In my case, I found it worth the cost of a slightly used pair of WE to find out. I'm glad I did. Good luck.

People are paying US$1000 for a single NOS WE300B and they are not stupid!

The cost difference is not in just the sound. With an approximately 40,000 hrs of usable service in the tube it is actually less expensive than others.