I know that Pro Juniors have their fans, but I’m really not one of them. To me, it has all the distortion of an old tweed amp and none of the charm. The circuit design is kind of a mash-up of traditional Fender tweed preamp and modern output stage. Pro Juniors are very noise-prone and tend to be fussy about tubes. Hiss and hum are part of the territory, although some lucky folks have quiet, well-behaved PJs.
I have some mods on my old pages and I have some others forthcoming that help with the noise and such. Sorry to be a party pooper; it’s just not my ideal amp.