I'll repeat what I posted in another discussion on the same topic, a day or two ago, here on this forum:
Whether the device being discussed is a slide stop or a slide release may depend upon how the gun maker chooses to describe it, or how you choose to use it... I've seen it described both ways in different owner's manuals.
The part in question, in addition to STOPPING the slide in the rear-ward position when the mag is empty, can also be used to RELEASE the slide when a fresh magazine is inserted. If the device didn't have dual functionality, there'd be little reason for that little a "push here" tab on the device, but 99% of all semi-autos have that tab. I've only encountered one that FORCED you to pull back the slide because there was no tab to press.
The US military, the last I heard, now trains those using handguns to use that device to RELEASE the slide when reloading. This change in the training method was based on a lot of problems experienced by troops under combat conditions in Afghanistan and Iraq. Most of those troops use Beretta M9s, not Shields, but the military's training (and re-training) tells them to ignore Beretta's guidance (which recommends using the serrations on the rear of the slide to pull the slide back and releasing.)
Some gunmakers, Kahr among them, tell owners that using the "slingshot" method with some of their models simply won't work -- as the round being fed won't go into battery properly. They recommend using the "stop/release" to send the slide forward. The Glock user's manual says to press down on the slide stop lever to release the slide. They call it a stop, but recommend using it as a release. A few other gunmakers do this, too.
One acquaintance, a fellow who has spent a lot of time working with and training the Special Ops troops at Fort Bragg, makes the point that the "slingshot" method recommend in the S&W manual for the Shield FORCES the shooter to move the gun away from the next likely target when doing a routine mag exchange. Using the slide stop/release to let the slide go forward -- if you can use it -- can allow you to keep the gun on or closer to the next target when inserting the mag and closing the slide. It may depend more on the gun or on the conditions in which you shoot, rather than what the device/lever is called.
Use the method that works best (and makes the most sense) for you, but don't be too adamant about what that device is called or how it is best used.