The conventional wisdom is that "the one to use it decides".
It appears from my perspective that you had selected something you were comfortable with only to receive post-decision advice that resulted in analysis paralysis, as it were.
Everything would have been just fine had the late breaking advice never surfaced as it merely added FUD and, as such, was counter productive. I suppose the same might be said for this thread in general and my post in particular.
What started out as a simple purchase of a used Glock has somehow mutated into a field populated by shotguns, revolvers, alternative autoloaders, AR-15 derivitives and will no doubt range even farther afield should you permit it to do so.
It is, by now, obvious that everyone has a different notion of "best" and it can even extend into the minutiae of used vs. new, malfunctions attributable solely to a hobby you don't have (reloading) and self-induced unclearable jams - a condition so unlikely as I can't even begin to guess what that was about.
You had already made a perfectly viable decision - if your intent was introduce doubt, you've come to right place. Certainly getting advice on a gun board will serve to expand rather than reduce the choices - we tend to dissipate rather than focus the process.
So, if it isn't about the firearm and actually is simple analysis paralysis, what does one do?
It's probably different for each of us. For me, a sharp blow to the head sometimes works wonders. Failing that the judicious application of Patrone Silver (chilled) combined with dice or I-Ching sticks or a magic 8-ball can provide resolution.
My personal recommendation is the Patrone with dice.
(The Patrone is only for dilemma resolution, don't shoot after shots.)
You were doing just fine until the unsolicited advice hit. It must be in our genes to overcomplicate simple issues and unresolve the already resolved.