Keep in mind there are different solders with different compositions.
I am afraid even when you buy the best Sn96Ag4, it will be nowhere near the worst Sn60Pb40 (when compared the mechanical properties, melting point etc). Add to that the decision about flux - there are dozens of different flux types, more and less agressive, no clean etc and of course there is a solid core solder without flux.
The Pb free solder for rework that I can recommend is Sn96Ag4 which is quite pleasant in use but since it is 4% silver, it is not cheap and it melts at 220degC.
Then - there is no significant difference in between soldering with Sn99.7Cu0.3 and soldering with a paperclip IMHO
. Any Pb-free rework with this 0% Ag thing requires top notch soldering iron plus a lot of flux and patience.
1kg of Sn60Pb40 is around $25 and 1kg of Sn96Ag4 is $100 (1mm).