Best way to find out is to try. I'd say they are as good but very different. The GEM blades are mellower, possibly more forgiving, so the artist club type blades it's probably fair to say are sharper. I'd say you are less likely to get irritation from a GEM blade.That's a beautiful razor. Are GEM blades as good as Artist Clubs? They don't seem to be as popular/common.
And honestly, that is what has prevented me from buying a Sabre.
You can still pick up 1912 pattern GEM razors in nice condition very cheaply on eBay so that is an option, or I've got a nice example of one that's a spare that I could send to you as a loaner with a couple of blades to try.