I had Oliver Sayes build me a custom unit based on the RH84 circuit. It's an amazing single ended pentode amp. It nicely showcases what the EL84 can do; it's hard not to like a well-designed, well-built EL84 amp. It's holographic, and I find it a tad punchier, and bass probably a little tighter, than single-ended triode amps I own and have used in the past. Overall, I'd say it has the air and liquidity that one usually wants in a single-ended amp, but maybe a little faster and a touch less bloomy than the typical SET.