Has this fallen out of favor?
I learned it years ago, and I tend to use it during training as my default low ready. The biggest complaint I've heard about it is that it tends to make people tense up. I've compensated for that by not bringing it all the way into my chest and assuming the hunched position I normally see people use with this. The way I hold the gun, it looks kind of like the unarmed ready position I see police use with their hands slightly touching near the solar plexus. I think I've heard it called the interview position.
If this is something that has been found to be less than optimal, what do you suggest as an alternative? I'm always looking to improve.
Sure. Why is that hand under there? What does that hand do to help your pistol hand? I dunno. Give me a reason to do this when the support hand can be of more help not there.
I am not going to get into a whole tactical thing. But I have worked 2 man covered movements in confined spaces and worked stacked on a team. Pistols are out and ready for a reason. This is definitely not of no need for those dynamic movements.
2 cops nonchalantly drawn walking through a house, that support hand is best used for other things, maybe to parry someone coming out a door, to move something, grab, use radio, flashlight, etc... You can hold that pistol the same way without that support hand under there.
Sometimes people get muzzled in dynamic situations. That's why we practice finger off the trigger until we shoot.