Its my only amp. I love it. It has a great clean. Its not glassy at all, its clear and almost chewy if that makes any sense, but it works because it doesn't tire out your ears with treble. It also overdrives perfect IMO. That's where it really shines. I rarely get to turn it loud, but when I do, it sounds damn nice.
I just put a Clark Regulator on mine. If you like tweed sounds, this amp is worth grabbing for sure. A unique feel and sound, maybe due to the two rectifier set up. Excellent speakers. It is ear friendly for such a loud amp. Really shines on a loud stage. Luckily, it also sounds beautiful at low and medium volumes.
I bought a new one a few years ago & love it so much, that I bought another one to gig with. It was 1400 used! You can find them used if you look around. I left my new one stock but I changed the tubes to the winged C's & I pulled a rectifier tube in my used one. With the rec tube pulled it makes it easier to gig with. It's pretty loud stock, you won't be able to get it to break up in most places. I own a bunch of fender tube amps & IMO the 57 twin is the best made!! Very versatile with your attack, semi-clean to drive with your hand, it's awesome!!
I just installed a Clark Regulator attentuator on mine. Very nice little device. On 3db cut, takes just enough edge off. Though in truth, this amp sounds so good at lower volumes, it's no hardship to not attenuate.
I test drove one of these delightful amps last Spring at my local store. While yours truly was happily riffing away, a Fender rep walked right up and changed the price tag from $1,999 to $3,099! I was shocked and more than a bit PO'd.
As for the amp, it's fantastic; plenty of Testosterone, even when clean. I'll bet the '57 Twin reissue would be great for Keef tone. I bought a Carmen Ghia instead. Nothing against the '57 Twin reissue as far as tone and build quality.