Here's a plug for the Decware Taboo, especially the mark II (because it's the one I own and haven't heard the mk III).
Originally a speaker-only amp it's a simple tube design - one rectifier, one driver and two power tubes. It's very responsive to tube-rolling, with the largest effects coming from changing rectifier and driver. Different rectifier classes set different voltage points which make the amp more analytical (crudely, 'SS'-like) or forgiving as the case may be. In combination with the driver I've found it can be made neutral/transparent (my preference) or more "tubey" as one likes.
I run my LCD3F and LCD2r1 balanced off the speaker taps, which sounds better than the provided SE hp out. The mark III provides both SE and balanced hp outs.
I haven't heard other serious tube rivals such as Eddie Current, Cavalli, Woo etc. However, it handily outperforms mid-range SS amps I'm familiar with such as the Violectric V100 and Meier Concerto and Classic. Key differences I found are micro and macrodynamics which provide detail and "liveliness" these other amps generally lack. Bass is tight and it's attack can be eye-blinking when it's there in the recording. With a good supporting DAC all the fine ambient information is there too...
(Note: Meier Classic though it is less lively does provide very precise layering which (edit) the 3F particularly benefits from and which I don't think the Taboo quite matches).