I am a HUGE SWR fan. I am loyal. I never understood how great tone can be in or out of style, but I do understand how some brands are so distinctive that they can sound dated.
SWR tone is timeless to me. I own many different SWR heads and cabs. My SWR Baby Blue II head gets the most of my attention for a few reasons.
1. It's lightweight and portable. Weighs less than 20 lbs. It's around 14 lbs I think
2. Iron transformer. No class D "fake tone" here. It's the real thing. Just like the legendary Mesa Walkabout head. I think they are about the same weight and both have iron transformers. I also own both.
3. Classic SWR tone. Actually, it is SWR at it's best. The BABY BLUE II has the pinnacle of SWR tone. Most fans say it's arguably their best amp ever. I would agree.
4. Ease of use. No stupid, useless gimmicky knobs. Just the essentials.
5. Volume. It's no Bass 750, but I've never regretted taking the BBII to a gig and not had enough volume. I usually take my Baby Blue II and my SWR 4 ohm 410 Golight cab and I'm set. It's loud enough and never had to turn up all the way. Even for outdoor gigs. If I'm onstage at a good club, the soundman will use the D.I. anyway into the system and my amp is a monitor, basically.
To be honest though, like the Mesa WA, I'd love to see the Baby Blue II as a 300w amp. I can add my SWR One Horsepower 750w power amp if I want thunder.
So, in conclusion, the SWR Baby Blue II sounds amazing with active or passive basses. No gimmicks. Just great tone.