I've been looking at buying a new soldering station since my old one has all but given up the ghost. But I'm curious about lead-free versus normal soldering irons. I understand that lead-free solder melts at a higher temperature, so I can understand why a soldering iron without a temperature control could be intended for one use over another, but if a company's product line includes two temperature controlled irons that both have the same temperature range, but one is marketed as lead-free and the other one not, what is the difference?