I don't know much about this stuff but I say KEEPER!
Where Obtained: gift
It doesn't look like much but it has a nice tube sound. I expect it is a lower end National.
I have used an SG copy and a Fender Bullet with this amp and well, anything named Fender is going to sound nifty coming out of it. It distorts quite nicely at the high end so that SG copy got rather nasty too if I needed it.
Its old and I was told too keep it that way - 2 pronged plug and oldish wiring.
Haven't cracked it open for any extended period of time. Just to check it out.