At this point in solid state design it was all about making power. I don't recall any of these manufactures making any claims of ultimate fidelity as one sees today.
We abused the 400s for nine years in a Road case and sold the setup still in working order.
Personally, I hadn't considered Bob Carver's designs since the 400s other than reading about his amplifier voicing challenge, cube subs, and his branding issues, until recently.
In shopping for high powered tube mono blocks and after reading about Bob Carver's collaborative tube circuit design I gave Carver's recent tube design a listen. I am very satisfied with their presentation, hand made yet sensible build quality, and their general performance. I am somewhat saddened and concerned by the recent sale of this little company to a large offshore manufacture who will be in trusted in maintaining the remaining seven year Carver warrantee.