Mention internal locks, especially S&W, and you open a big can of worms. Some are ok with the idea, others dislike the specific manner S&W chose to incorporate them, and others of us are against the idea completely, either on principle, or because of the enforced nature of the locks.
First, lets look at the basic idea behind the lock. The plus is, that being built into the gun, it is always available. On the other hand, I think that is the only plus. Personally, I am against the idea of putting a lock on a loaded gun. And ESPECIALLY a trigger lock. Yet some people think its ok. THey feel it gives them the a safe way to store a loaded gun.
I have never understood the utility to locking the gun. If it is unloaded, it is hardly a risk. SO, why lock it? And locking a loaded gun, thinking that they are somehow saving some time, all they have to do is unlock the gun, right?
Being who and what I am, and knowing that under extreme stress I do have issues with "fine motor skills", I find it much easier, and faster to load a gun that is unlocked than fumble with a tiny little key to unlock a loaded one.
Also, there is the idea that any unnecessary mechanical addition to the gun increases its complexity, and gives us one more thing that can fail. And, Murphy being alive and well, it is virtually guaranteed to fail at the worst possible time.
There are documented cases of internal locks "failing" meaning auto-engaging, and stopping the gun from firing. Not a lot, but there are some. Some of us don't find even this small risk justified. Especially when it comes from what we consider a non-essential (or non useful) part.
because of the risk of fumbling and failing to get your defense gun unlocked in time, and the risk of having the lock "fail" to unlock, or having it lock on its own, I'm part of the culture that says "you don't lock your gun. You lock your gun up!". Meaning, if you need it secured, you secure it IN something (lockbox, safe, etc...)
The S&W lock, in particular is still a heated issue for many. The British holding company that owned S&W during the 90s voluntarily bought into an agreement with the Clinton administration, which consisted of many parts, most rediculous backdoor gun control, and some possibly illegal...
As a sign of their "good faith" that Brit company made S&W put the locks in, and the fact that they put them in, and where they put the "Hillary hole" upset a lot of us. S&W got boycotted. Their stock tanked. The Brits wound up selling S&W for a large loss.
I won't buy a new S&W with the lock. I know a lot of people with similar feelsing, too. There are still plenty of the older guns, (in some cases made better, too) to satisfy our needs. Yes, that does mean that I am delberately limiting my options, but that's my choice.
All else being equal (and it almost never is) bigger bullets tend to work better.