Coot,
Another amp I have used to good effect with my 5s as a pinchhitter for the BCs once is the Tube Audio Design 125 Hibachi monoblocks. These are an absolute steal usually at under $1000 when the y come up for sale here. Unfortunately, TAD was a one man shop and the designer and support guy who was great with service and communications passed away recently,
The TAD 125s are 180w/ch and go for more of a tube amp sound in a mostly SS package. With my 5s, they are lovely all around with a particularly vivid midrange. Ultimate bass authority, slam and control is just a tad behind the BCs at most normal volumes. THe BCs however just continue to expand the sound effortlessly as the volume goes up whereas the TADs will start to compress a bit sooner.
I use the TADs normally with my smaller 100S3 OHMs and they are a perfect match there!