I've got a Checkerboard R55 that was formerly owned by Rick Nielsen. I plugged it in tonight for the first time in a long time- and the thing is just magical. The "British" channel is absolutely wonderful- plenty of punch and it has this creamy Marshall tone for days. Then, on the "American" channel you've got wonderful cleans that just shimmer. I don't see a ton of them around, but I think these Rivera's are absolutely amazing. There, I'm done.