Checking my fridge drawer: I've used leaded mechanic paste, and SAC-305 mechanic, SRA, and MG chemicals (plus chipquik low temperature bismuth paste, but it was terrible: I had parts literally falling off the board).

They're all significantly worse for stenciling than GC-10. If you're manually applying paste with a syringe, you might be better off with other paste, because it's significantly thicker than the usual pastes I've tried, but I usually just hand solder instead of waiting an hour for refrigerated paste to be better.

When this tub of GC-10 actually has any symptoms of being expired, I'm definitely going to buy another (or maybe GC-18, which seems to be the new shiny version? I don't see any ebay listings for cheap almost-expired GC-18, sadly.)