Lead-free solder is kind of embarrassed like old people, but it does not matter if you get used to it. Because mechanical strength and conductivity (electrical resistance) are excellent, there is no hand that is not used from the influence on the environment. To tell the truth, I have not tried other varieties much. After all, it is necessary to increase the number of work and get used to it. There is no gloss on the finish and the flow of solder is also quite different as compared to lead containing light. The flux will be improved, I feel that the reliability of the connection is certain. There is little worry that electric resistance must be earned because electric resistance in the first place is low. It is important to note that continuity can not be confirmed by lightly testering it, although it is not known whether the surface is hard due to the conduction check after finish or whether the surface is oxidized and the resistance is high, so be careful.