My most disturbing issues came from different grades of the same action type.

I usually shoot open, with a trigger beat measured in ounces. I tried to shoot a stock 1911, and stopped pulling the trigger and tried to clear the gun, because I had not shot one with a 5# trigger in many thousands of rounds

Similarly, I shot "hot" defensive Ammo through a 1911, and stopped to check the gun after what I thought was a double charge.

I now have 2.75# triggers on my carry 1911s, as they're still double my competition triggers, but I will still pull them, and carry lighter defense loads, as +P 45s don't make much sense to me.

I started with a 1911 pistol, in late 1982, or 1983. Some time later, by late 1983, I added DA revolvers, because I started a police academy, for a department which mandated that cadets and first-year rookies carry only DA revolvers. I have always been able to move back and forth between these two systems, using both together.

In 1991, I added a SIG P220 "E" pistol, and all was well, except that the heel-clip magazine release sometimes snagged the seat bolster on patrol cars, allowing a partial magazine drop, so I reverted to revolvers for most purposes. Actually operating the P220, however, was not a problem.

I tried a Browning Hi-Power some time around 1994, and did run into a problem, sometimes forgetting to operate the thumb safety. I never had this problem woth a 1911, but it happened with the BHP. Perhaps my brain perceived that I was handling a P220? The old-style P220 "E" and the BHP both have curved-profile back straps.

I did not replace my P220 "E" with the more modern "American" style P220, because it pointed low in my hands. I continued to mostly use revolvers.

I tried a couple of semi-compact Third-Generation S&W pistols, in the mid-Nineties, and while I never missed properly operating the safety lever, never learned to like that it operated differently than a 1911 safety. I kept using mostly revolvers for serious purposes.

I shifted to mostly using 1911 pistols, in 1997, for duty and personal carry, with revolvers mostly as secondary weapons. Still, there were no problems using these two weapons systems together.

In 2002, however, I discovered that my then-mandated duty holster was interfering with my ability to attain a proper firing grip on 1911 pistols, to the extent that I would not always depress the grip safety far enough, unless I shifted my grip after the draw. By this time, my PD employer had moved to all auto-loaders for uniformed police duty, except for those who took the steps to "grandfather" their revolvers. This prompted me to reluctantly enter the "modern" era, and use G22 Glocks as duty pistols.

I continued to largely use revolvers as back-up and personal-time carry guns, experiencing no compatibility issues. I was frustrated with my accuracy with Glocks, so in 2004 tried the new SIG DAK system. I found that the P229 pointed well in my hands, unlike the "American" P220, and the thinner-profile short-reach trigger (not SRT) was better for me than the earlier fatter-profile trigger. The DAK trigger worked like my revolver triggers. Sweet!

I then ran into a compatibility problem, with the longer reset of the SIG trigger. If I trained with DA revolvers and SIG DAK, all was well, but if I shot a Glock, and then immediately shot the SIG, I might flub the reset of the trigger. So, my Glocks went away, and all was well, until the muzzle flip caused by .40 recoil, and the high SIG bore axis, became too much for my aging hands. I started working my one remaining 1911 pistol back into my personal carry ensemble, because a full-sized, all-steel, low-bore-axis .45 ACP 1911 has different recoil characteristics than an alloy-framed, high-bore-axis .40

In September 2015, my chief provided relief, by authorizing
9mm as an alternative duty cartridge to the previously-mandated .40 S&W and .45 ACP. I reverted to Glock, in 9mm this time. To prevent trigger-reset compatibility issues, I retired the P229 DAK, which hurts too much to shoot anymore, anyway.

I have no problems using Glock, 1911, and DA revolver systems, except that getting top-level accuracy with Glocks is frustating.

Is it a best practice to use only one handgun systems? Ideally, yes, but I manage OK with three.