Why are you guys still arguing this???
If you don't like the ILS in the S&W revolvers, don't buy the guns made with them after 2000. If you like the Centennial style guns, S&W offers some of those models made without the ILS, so you can still buy those.
In the meantime, I just had someone bring in a NIB S&W M617 in which the hand spring had somehow gotten loose and stopped the hand from indexing the cylinder. The long spring leg got caught up between the moving parts and was cut off.
(Oddly enough, nothing seemed to be wrong with the ILS in that gun.
Never saw that happen before, and probably won't again, either.
As an armorer, the ILS is the least of my worries when it comes to maintaining/servicing S&W revolvers.
Everybody else among the internet gun forums can argue about it as long as they care to do so.
Buy what you like, and don't buy what you don't like. Simple enough.