I have usually used the release. However a friend in Texas that works at a range advises to use the slingshot method on Glocks especially. He has seen broken ones and replaced the slide releases on a couple. He is even a Glock fan.
Now on my G44 I found that using the release will cause it not to feed, so I use the slingshot method.
I noticed on the MAC review he was told the same thing about the 44. I have a feeling it allows a shell that is not sitting quite right in the magazine to pop in place and feed better. The last 3 rounds of those mags are crucial to letting the gun work correctly. Just something to think about.
