I don't think you will find 60/40 lead free - the 60/40 is 60% tin and 40% lead, while the lead free has a much higher percentage of tin; 99% or so AFAIK.
I'd say the 60/40 with lead is a better bet, as the lead-free has a higher melting point so needs more heating, causing a greater chance of overheating the pots or something.
I'm sure someone else will correct me if this is wrong.