Personally, the thought of re-tubing a full-on tube amp (both the expense of good tubes, and a proper tech to perform it) renders this a non-question for me personally. I want loud and clean and consistent, and if it weighs five pounds and goes in a shoulder bag, I'm good. I can't hear whether it's Class D, Sunday School Class, or Late for Dinner.
80 pound heads and a pile of tubes is not a life I want to lead, no matter how good it may (or may not) sound. I do like the tube preamp in front, solid-state power in back rigs I've heard, but that would be as far as I'm willing to commit to that technology / topography, with a single preamp tube that lasts a long time.
I've never found tubes / no tubes a red line I can't cross, in fact, I've never seen the line.
I'm quite sure your results may vary, but that's this one man's opinion.