Is it safe? That is the question.
I've been using hackintosh for a while, and it's almost a vanilla OSX with the exception of Clover and FakeSMC. I doubt there's any malware in there...
Famous last words. Unless the builds are verifiable, they're not trustable. Open source doesn't do you any good if you don't know that the binary that you download and run doesn't do something weird.
Open source gives you the possibility of knowing your binary is good, by compiling it yourself. I chose not to do so, because I couldn't really be bothered. But others who need this kind of security could, and I would hope they do.
Would all that is necessary be to put the Hackintosh behind a network inspector, say Wireshark, to check if anything nefarious or unexpected is going on.