Here is the update of my previous test of SinFP.
I compared then the output of SinFP and Nmap on different machines, and found out that SinFP made a slightly better job than Nmap in OS detection, though it is not the primary goal of Nmap whereas it is the one of SinFP.
However, I made a mistake that the author of SinFP made me aware of.
I conducted the tests of Nmap using the package of my distribution, thinking it was the latest one.
Actually, it was only the version 4.10. Moreover, the current version, 4.20, brought up a new OS detection engine.
Therefore, a new test with version 4.20 was absolutely needed.