Mapman,
Good questions, I`m just a consumer and certainly have`nt heard every competent SET available. I can say that the SET amps mentioned in the above posts are very good. Personally I can speak from experience with the Coincident Frankenstein MK II(retail 6,000.00 USD).It`s truely a superb 300b amplifier and improves further with the best brand output tubes(for example Takatsuki or Sophia Royal Princess). But there are others as well. There are top quality 845 amps(I`m less familliar with these). I`d say 5-12,000 USD retail(obviously less if used prices) would buy a top level SET with high quality transformers, parts and power supply.
I don`t doubt the performance of the Wavac EC 300b at 30K, but I don`t feel the other suggested amps would be embarrassed at all head to head IMO.