The biggest problem is getting them shipped safely as many sellers don't have the original packaging nor the knowledge to correctly disassemble the table/arm and pack it properly to avoid damage during shipping.Worried about shipping? That would imply buying a vintage TT online from a vendor like Ebay and that poses a whole other problem - trusting that the TT works at factory spec despite what the seller says. Most selling vintage on line really have no idea.
If your going to go vintage, buy only from Craiglist or a local shop where you actually inspect and hear the TT before you buy it. Or your going to get burned.