Yes I prefer the 6CA7 over the EL34 which is generally used in the Sound City 120. As you say, clean and warm.
While the wiring may appear unorthodox for a hand crafted valve amp, it is totally stable and virtually silent even with the volume rolled right up. Rob spent some time getting the Boogie 120 just right and clearly wasn't going let me get my grubby little hands on it until [u]he[/u] was completely happy with it.
If you want something really special built to very high standards for what I consider to be a most reasonable price, I wholeheartedly recommend you give Rob a shout.