Given the damage in my left shoulder, I am far quicker using the slide stop/release lever on all three of my Glocks (21,30,34) - if the mag insertion didn't already release it (and yes, I like it that way). OTOH, my wife can't operate the multipurpose slide lever on her M&P 9c to save her life - but she can't slingshot it, either. She has to hold the gun in tight, grip the slide, and push the grip forward. She almost never is able to lock the slide open manually. This was problematic when she had to demonstrate safe gun handling at time of purchase. We solved that by having her drop the loaded mag and insert an empty one, then rack the slide to clear the chamber and lock the slide, then drop the empty to show clear.
When I shoot a 1911, I use the release. I have, however, practiced alternative methods of one-handed slide release on every gun I've carried. I also practice shooting one-handed weak-side, which becomes increasingly difficult with age and deterioration of body parts.
Does anybody even know someone who has worn out a slide lever? Use whatever works for you. Practice it until it's second nature.