IMHO, valve bass amps = more weight, more bad backs, more reliability issues. No matter how well designed and built. You HAVE to know how to look after them properly to achieve the best reliability, and have the ear of a good tech to service them regularly. All this is great if you're happy doing that, but they're not cheap to get serviced, no matter how you slice and dice it. And I'm saying all this as an electronics tech who was trained on valves, and is rather fond of them. I just would not be so crazy as to take out something weighing any more than the 6.5lbs of the LMII. There's simply no point...And if what you want is clear, clean power, SS is easily the only way to go.
I do want a valve amp. I want a silverface 50W Fender Bassman and 2x15, as I used to use in the Penguin Night Club in Swaziland, in 70/71. That would now be my home practice rig!