Shok-buffs are not for everybody and not all guns are machined with enough clearance to allow for the extra room necessary for a standard (.100-.105 thick) Shok-buff.
I have 5 5" .45 autos that I use for indoor target use and all are equipped with Shok-buffs.
Les Baer, at least older Premier II's generally will not accept a standard (.100-.105 thick) Shok-buff and have enough room to slingshot, something which I consider necessary for at least target guns. (May or may not hold slide back / open on last round fired).
Ed Brown, at least the Executive Target models, do not have enough room to run a standard thick (.100-.105 thick) Shok-buff and have enough room to slingshot. (May or may not hold slide back / open on last round fired).
Wilson Combat issues all of their 5", at least their .45 autos, with Shok-buffs. They do not believe in using Shok-buffs with less than a 5" gun.
Shok-buffs can cause problems and are not for everybody.
Shok-buffs, just like FLGR's, have lots of haters.
I use FLGR's in all of my guns also.