The wooden front and back pieces frequently dry out and crack/split in some places. That doesn't affect sonics but it is a cosmetic blemish to be aware of. I oil mine twice a year to try and preserve it, but I still have a crack.
It can come with either a balanced or an RCA input, so get what you need for your rig. Other than that, check the tubes. The standard tubes are actually pretty good. Apparently Jim treats them in some way, but you can get better sonics by tube swapping. Ask if the previous owner is including any othe tubes with it.
