Just the name sends shivers down my spine:)
Yes it is a Bongiorn design. It is a less powerful amp than Ampzilla. I had one of those and they are both fine amps. He also made Charlie the Tuner...I loved that name. As I recall, there are people who modernize these amps and make them very much better...like the Dynaco products. In their time, they were very admired...Stereophile and Absulute Sound liked them.
It depends on if you are talking about the Son of Ampzilla or the Son of Ampzilla 2000.
James has been manufacturing the Son of Ampzilla 2000 for several years that is an updated amp built by Cullen Circuits.
It is rated @ 100wpc @ 8 ohms and 200wpc at 4 ohms.
However out of all those replies not a word answering your question about if it is/was good.
In general the "Son of Ampzilla" of the 70's was considered quite good for the times.
The newer version "Son of Ampzilla 2000" and the "Ampzilla 2000 Monoblocs" are also exceptional performers and well reviewed by several reviewers including Tony Cordesman.
The reviews can be sourced on the Ampzilla2000.com website.
I think Dick Olsher has written a good review of the "new" Son a couple years ago.
Son of Amzilla Review
Years ago I had a chance to meet James Bongiorno when he was showing off his then new Son of Ampzilla at a local audio shop. I bought one, and used it to drive a set of Magnepans for a number of years. I really enjoyed that system and amp.
I recently picked up a Son of Ampzilla 2000 to drive my NaO speakers. The SOA 2000 is a very fine amplifier. It's also built like a brick outhouse.