(most) Tube amps do have issues. Heat, tube life, tube matching, and the fact that iron core output transformers add a lot of chassis weight and distort the music that you don't realize until its gone.
Check out Linear Tube Audio, which licenses David Berning's ZOTL design. I'm running ESL speakers with the ZOTL40 amp, which really puts out more than the rated 40 watts/ch. At least with my speakers, the speaker/amp handshake is just about perfect. If needed, it can be bridged as mono for nearly twice the rated output.
The amp weighs less than 10 pounds, tubes last 10-20 years because they aren't run hard or spew a lot of heat. The sound is so clear and linear you think SS except you are hearing the beauty of the tubes, not the iron transformers. I run a quad of NOS Mullard XF2 EL34s, hard to beat.