Got some Head finest calfskin when they were available for 15 EUR a piece. Now at 20 EUR, I'm reluctant to get more.
But I also have some Head leather tour, Gamma, Prince, Dunlop, Pacific, and Oehms. Out of these, Prince and Dunlop are basically the same, very soft and comfy. Gamma is the hardest, Pacific is close, and Head leather tour is middle of the road. Oehms claims their leather grips are from the same manufacturer who supplied the finest calfskin grips to Head years ago - not sure if Head has another supplier now or if they've changed these grips over the years. The Oehms leather grip is indeed very similar to the Hfc, albeit not exactly the same as far as I can tell. Oh, and the Hfc is indeed my favourite out of the ones I have. Medium firmness but nice feeling.
That would be underneath an overgrip for all these leather grips - you do feel differences even then!