Being the proud new owner of a NEW S&W 642-2, I'll give you my first impressions of the big bad lock.
I wouldn't have noticed it if the owner of the shop hadn't pointed it out to me... It's a tiny little thing on the side, very similar to the Taurus locks. On the other hand, the ones on the bottom of the trigger guard, the ones designed by S&W's new owners, available on most S&W semi-autos, ARE ugly indeed, and do screw up the "lines" quite a bit, IMHO.
I don't have any problem with UNOBTRUSIVE internal locking mechanisms on my pistols.
All the ones I've seen internal drawings of are ACTIVE when locked and PASSIVE when unlocked. Which means, the commonly heard statement
Any mechanical device can fail.
only has merit if you're talking about LOCKING the pistol. If you leave it unlocked, it's out of the loop.
While we can all imagine up some hypothetical way that a these locking devices COULD fail, has anyone EVER had one actually rendered a firearm non-functional while in the UNlocked position? Quite honestly, show me some real live cases of that, and I'm in the boat with you.
Until then, they're just like the locks on my Dodge pickup. I didn't ASK for door locks, and I don't have to USE the door locks, but they are there nonetheless.
But as I do enjoy pointing out... (applying to most subjects, first time for this one in particular)....
If you decide don't like internal locks on your firearms, and you absolutely refuse to buy a firearm with an internal lock, and you think they're ugly as sin...
God bless America!