There is no doubt that these are respectable projects. I also believe that a solid-state side-chain is perfectly capable of delivering the same performance as that in a true Fairchild.The Poorchild 660 by Analag and Silent Art is one of the best, if not the best, DIY mu-comp project of all time imo.
What I contest is when someone says that a side-chain based on a dual triode with no significant iron is capable of delivering the same perfomance.
Or that the same performance as a quartet of 6386's can be achieved with a single dual vari-mu tube.