Factory. They haven't failed me, so why should I change.
I see little use for tritium sights. The only time they are really useful is during dawn and dusk hours, and that isn't long enough to warrent the high price of them to me. One can still see the front sight well enough at night when a good flashlight it used for long range shots. And if your shooting inside 7 yards, which most handgun situations occur in, you won't have time to look at your sights to line them up, you'd better be natural at it.