I've fired a few thousand, but all in .38 Special so I can't speak to anything else. When I get around to it I have a couple of guns I can think of to try them in. One is also a striker fired .380 and then I have a Springfield 1911 in 9mm that has always been reliable but doesn't make much of a primer impression.

The question is not so much whether they are, or are not, harder but does it make ignition unreliable.

If an 18oz hammer swung at full force will punch a hole in 1/2" sheetrock, will it punch a hole is 5/8" sheetrock?

You might find a gun with marginal firing pin force where it would be a problem. Kind of like, in the scenario above, if I gave the hammer to my four year old grandson. You'd find somebody who punched a hole in the 1/2" who couldn't in the 5/8". But it is likely a small sample.