Personally, fiber optic front sights have helped me get back a good deal of the relative speed and precision with which I can deliver good shot placement that had been deteriorating with advancing age. This had become especially apparent when I began to need bifocals. The "lineless" progressive lenses do allow one to find the "sweet spot" where you get decent definition of your front sight, but it's very difficult to maintain that focal point when transitioning between targets and/or shooting positions.
I don't consider conventional fiber optics as being "night sights". The ones I've tried and currently use need for there to be quite a bit of ambient light present to work well, certainly more than is likely to be present in many, if not most, SD/HD situations. That's basically why my daily CCW and "nightstand" weapons still wear tritiums.
FWIW, I've found that putting fiber optic front sights on my most used recreational longarms to be of even more value, as what once was too "fuzzy" to allow me to put my hits where I wanted them is now much more clearly defined and at least an order of magnitude faster to pick up a good sight picture.
The only way a TriLux could "quit suddenly" would be to rupture the vial releasing the tritium & that would take some serious doing as the vials ate strong thick & well protected.
