there is no such thing as a "tube" mic sound of course.
IMHO there definitely is. although it might not make much difference for rock concert "taping" purposes. there are timbres and sounds you just can't with any other microphones than with a tube microphone. For example on anything acoustic like a piano, voice, acoustic guitar, cello, if you "push the tubes" in the microphone, the slight even harmonic distortion can be quite pleasant and nice sounding to the human ear. So many classic rock vocals are solely because of LD tube microphones. Of course different tube microphones have different sounds but that same "tube feel" is there.
same thing with microphones that have transformers and those without them. Ribbon microphones even have a distinct sound to them as well.