I had one, it was stolen. a good head, pretty loud with a 115. from '72 or so I believe. had a nice distortion control. I would get it you will like it, though it depends what you are trading for it...
I own a Peavey Century, but might not be the same one. Mine has pre & post gain so it makes a great guitar amp as well as a bass amp. With full bass & treble, I get great sound. I also like the pre out so I can drive an additional amp. I'm using a Crate Vintage 50 watt tube amp along with the Century on a full stack of 8 12"s. The Peavey on the bottom cab gives bass & punch, and the Crate tube amp gives great color and brightness. Both amps together sound like a bunch of Marshalls playing at the same time. I absolutely love it. I also bridge the Peavey to a Sunn Coliseum 300 watt bass amp into a 18" folded horn cab. It sounds so much better than just the Sunn alone. The preamp in the Peavey is perfect with no hum. I'll own the Peavey until the day I die.
Found this old thread while doing a search to find out what I'm playing through in my friend's basement - it's this Peavey Century 120. I hate it. I'm not any good at playing bass, but I really hate the sounds that come out of this amp. Maybe it's just the cab (118?), but I suspect it's both the head and the cab that sound like crap. Very undefined. I can get decent low-end except on an open E - it sounds TERRIBLE then. I absolutely avoid striking my E string without fretting at least an F#. And playing on the G string doesn't come across very well either. So essentially it is just okay in the low-mids and mids, and terrible everywhere else.
I can't wait to find something I want to spend money on so I can take a new rig over to their basement and they can give this thing away.
Anyway - just wanted to put my opinion out there in case anyone stumbles across this thread researching whether to buy one of these amps. I would recommend NOT buying one - I'm positive you can find a better amp out there.