What is the magic behind SET

I'm finding this to be a fascinating thread.

My system is comprised of a tube preamp matched to a solid state amp, but I've been very curious about possibly getting a SET for use as a second amp.

I'm just not sure which tube design to go with. Mostly likely I'll try an amp that will deliver the full bloom story, but I'm not sure if it will be a good match for my Blue Circle preamp which already has this slight characteristic.

Tom, your post really got the rusty cogs turning in my head. I blame you! Heheh.

C123666, are these the interstage coupled amps you referred to in another thread? Could you guys list a few? I'm very interested. Thanks!