In ’68 after CBS bought the Fender name from Leo Fender (the originator) a few adjustments were made to many of the amps… Most notably the silver face, but the electronics were changed some too. This was in responce to the rock and roll craze of the 60’s in order to make the amps louder. However, in doing so it sacrificed some of their tone.
Silver faces are cheaper and almost as good, and if you can find a good tech you can have them "black faced" which is where a few changes are made to bring them back to pre ’68 standards (the face will still be silver though.)
If you want a really good amp that’s a little smaller than a Twin, I suggest a Deluxe-Reverb… It’s what I use. Also, Fender didn’t make a whole lot of changes to these so the silver faces are still really good. Still the closer to ’68 you can find them the better. I have a ’68 model (because I was lucky [img]http://www.freakscene.net/ubb/smilies/biggrin.gif[/img] ) ’68s are identifiable by a small aluminum frame around the grill cloth…
a lot more info can be found at the link below, including dating methods…
I hope I’ve been some help,
"If you can’t pay money… At least pay attention!" – My Dad