I've always wondered if these are worth it.
I actually use "Gas Blowback" Airsoft replicas for this sort of training in my apartment. There is a lot of junk, of course, but if you know what you're looking for you can find some very realistic replicas that function just as a real fire-arm - you can actuate the slide to chamber the initial round, or on reloads, and the slide blows back as you discharge a round. Everything else is generally fully functional as well - safeties, slide release, magazine release, etc. It's a great tool for getting familiar with a weapon. You can even have, for instance, that satisfying result of inadvertently actuating slide-mounted safeties when you rack the slide to clear a jam or reload, and then wonder why your weapon doesn't go bang!
The only drawback to using Airsoft replicas for this purpose is that the slide spring, and (sometimes) the trigger spring are both far less stiff when compared to the real thing. Also, because the gas which powers the weapon is stored in the magazine, and not individual shells (in fact, the rounds are not contained by any shell, which means you can have double feeds if you rack the slide with a round already chambered, as racking the slide does not generally eject the previous round - not on most models, at least), the weapon will only function if the magazine is inserted.
They are overall great tools to build muscle-memory and work on trigger control with, though. And if you're fine with tinkering around, you can usually get after-market parts such as stiffer springs to give you, for instance, a stiffer trigger more akin to the real weapon.
So, as much as I like where that product is going, I do wonder: what does it offer that neither an airsoft replica, nor dry-fire practice with the actual fire-arm do? I guess a trigger that better approximates the feel of the real weapon is a huge plus, but the fact that the slide and other features do not function is a bit of a draw back. I do like the laser, though - as it allows for quieter practice. Shooting even a gas-blowback airsoft replica can still be kind of loud in an apartment.
