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Solder Alloys Test - Lead and Lead Free Solder : 60/40 - 63/37 (Eutectic) - 99.3/Cu0.7 - 99/Ag0.3/Cu0.7 (SAC) - 96.5/Ag3/Cu0.5 (SAC305)

60/40 and 63/37 shiny like mirror, experiment when soldering is same and price near similar, if you want low price choose 60/40
99.3/Cu0.7 (#1), 99/Ag0.3/Cu0.7 (#2), 96.5/Ag3/Cu0.5 (#3)
#2 and #3 shiny like aluminum (similar aluminum case of macbook), #1 shiny like fusion between mirror and aluminum. If you want use lead-free and shiny like lead, choose #1
Temperature soldering #1 #2 similar, #3 lower a little bit. So, feel when soldering #3 easy a little bit than #1 and #2
Price #1 #2 near similar, price #3 approximate double of #1
#1 #2 #3 need high temperature when soldering, so have risk that can damage chip if you hold soldering iron for long time
if you want use lead-free and no problem with money, choose #3 and soldering as fast as possible

So, choose Lead or Lead Free ?
Nothing is perfect. My conclusions
Lead : best for soldering
Lead Free : best for health & environment
I recommend use Lead Solder, except your application require RoHS or you care about health & environment