I bought one of these, with the OEM S&W laser grips - the ones that come from the factory with the S&W logo on them:
Here's a couple of good articles about it I found when I was researching:
Smith & Wesson Premiers Model 642 J-Frame with Crimson Trace® Lasergrips® at Industry Trade Show
Lasergrips plus S&W 642 equals value
The one thing a shooter MUST realize about this type of sighting is that you are no longer looking down your barrel at the front sight - rather you're looking totally beyond the gun at your target. For those of us really trained at acquiring a sight plane down a barrel quickly this can be quite an overwhelming change of attitude - at least it was for me. It's a totally different sighting system, and like any firearm sight it takes practice to be good at it. An excellent iron sight shooter that's never tried a laser sight will be in for lesson for sure...
I've become pretty good with the laser, but I've learned that I'm still more accurate by turning off the laser and going with just the rudimentary iron sights - plain & simple. I will give those cush grips kudos though - they really absorb the recoil!
But here's an overall observation from a traditional shooter like me. I bought this gun for the smallest capable CCW weapon I could find, one that could even go in my front pocket if I desired. Well, between the fact that I preferred the iron sights, and the fact that cush handle was truly one heck of a lot larger than the old traditional wood grip panels, I decided to take off the laser grips and put on a set of Chief's Special panels:
So, for the past 1/2 year the laser grips have been sitting in a bag in the gun safe. Guess that tells ya my personal thought on how much extra value the laser brings to me. I'll keep the laser grips if for nothing else if I ever care to sell the gun - I figure the OEM S&W grips will be of value someday down the road...
Oh, as for the ability of the laser grips to hold a true sight - they do. The beam is fully adjustable with the supplied ultra tiny allen wrench - I don't think I've ever seen a smaller allen wrench in my life. Very accurate, round after round. If you take the grips off at cleaning time you will sometimes find the smallest tweak is needed of the laser to true it all up again once the grips are back on.
Ya know, I'd find this gun with its laser to be one an excellent choice for the infrequent, non-tech shooter. The type of shooter that naturally looks at a target and pulls the trigger, or a point shooter. Sight plane down a barrel and following the front sight is something we acquire over time.