What qualities about a tube amp are most important to you?
tonality? many tube amplifiers sound neutral, many sound midrange forward, many sound rolled off at the high end, many emphasize midbass.
sound stage? most tube amplifiers project a large, spacious, atmospheric multi dimensional sound stage, something I have never heard in an all solid state amplifier to the extent a tube amp can project.
refinement and clarity? you can achieve or not achieve this with tube or solid state designs.
dynamics? same as above, tube or solid state amplifiers will deliver or not deliver depending on amp selected.