Since we are talking about a close range defense weapon and not a hunting or target pistol, I will default to Murphy's law.....what ever can go wrong will go wrong and at the most inopportune time.
S&W revolver sites (Adjustable) always had a taller but very ramped front site, not so on the taller semi's, it is just a snag waiting to happen.
Adjustable sites make a pistol more versatile, you can do target shooting, pop a coyote or other small critter, and yes self defense. But it is a compromise, a defensive pistol is a fighting pistol, a tool with a single minded purpose. Anything that gets in the way of it being the best fighting tool, is something that should not be on it.
A fighting pistol should have smooth snag free fixed sites.
Just remember if you really want adjustable sites, then buy a second pistol, use it for the non defense roll.
Your an American damn it, you can have more then one pistol.