I love my little gig bag Aguilar TH500 for “quiet” gigs. Does it sound anywhere near as good as my Sunn? Holy hell, no. Not in a million years and it never, ever, ever will. But it still sounds damn good. I’ll rock a Peavey Mark IV through a Crate cab if I have to, I don’t care THAT much. House backline generally trumps hauling my own amp, regardless of how crappy it is.
However the weight of my tube gear isn’t an issue. I spend $100/month on a gym, why am I going to complain about lifting an 80 pound head once or twice a week? It’s shagging exercise! Come on, we’re bassists, not guitarists!
Size is more of an issue. I drive a Prius. In one band my rig consists of a 2x15, 4x12 and two tube heads. Do I need all of that? Yes. In fact I could probably use more. But I’m in the process of downsizing just for the sake of not having to ask someone else to haul half of my rig. I mean it’s still cheaper than getting a van.
Class D was a definite consideration. As was class A/B. But at the end-of-the-day I wanted tubes. Because tubes amps sound better for this particular genre. It’s just more musical. And bigger cabinets move more air. And “low stage volume” gigs don’t sound as good. I made some compromises but will still get the sound I want. But if I had roadies and an 18 wheeler it would definitely be rows and rows and rows of big-ass tube amps.
There’s also the cool factor. A little class D with a micro-cab is kind of like the clip-on tuners of amps. Which means it’s like wearing a pair of Crocs on stage. “But it’s all about the music!” Sure it is. Nice Crocs, buddy.