It hardly matters since they’re exactly the same in effect when the classes are locked to a single character.
I suppose the only exceptions that matter (as far as I’m aware) would be with something like the Shamshir and Wo dao, as they’re myrmidon class only.
Also, Exalted Falchion can be used by Chrom or Einherjar Marth (try it), but not Lucina, so it’s not tied to class, I don’t know what the “Colussus Axe” is, and Omega Yato is locked to Corrin and works regardless of Corrin’s class (so long as the class can use swords).
I’d say it really depends on what you’re going for with the weapon, although generally I prefer character-locked weapons as they function as a buff to the character rather than class-locked which act as a buff to the class. Again, if the class is as unique as the character and reclassing said character isn’t an option, it doesn’t matter.
Not exactly, in my example Corrin can reclass but can’t use the Omega Yato unless they’re the (for example only) Valla Noble class as a result that gives an additional reason to make Corrin’s class the character exclusive class, because otherwise it can’t be used.
Honestly, can’t really decide on which I would prefer, since I actually like the idea of both prf weapons and class locked. As long as they help the class or characters with some of the trouble they are having, or give them more of an edge as other characters or other classes, they’re pretty fine.
Spoiler
One of the FE hacks, Project Ember, pretty much does both class locked weapons and prf weapons very well for the most part, like giving two kinds of sword ranged weapons that are both Myrmidon locked and Thief locked specifically to make up for the lack of ranged options, or giving Sophia that Basilisk Dark Tome, which gives her more than enough to not only have much better time with getting by that Desert chapter and later chapters, but gives her an edge in killing those wyverns very easily, that were very problematic for her during that Desert chapter in the Vanilla FE 6.