Flip-Stop vs String M, anyone use either or like them?

I'm looking at these "Flip-Stop" Cam Carabiner Stabilizers – Avant Climbing Innovations and these STRING M - Carabiners-And-Quickdraws | Petzl USA  

Thinking about adding them to alpine drows and racking like metolius' long draws, and or adding the string m to cam slings.

Anyone try either of these for alpine draws or have a comparison?

Direct from the Avant website:

*Note: Flip Stops are not recommended on alpine draws or extendable cam slings due to the added risk of unclipping fully from the sling during extension, but not realizing due to the carabiner being held in place by the rubber device.*

[edited, hyperlink added]

Not recommended for alpine draws, extended slings, etc, fyi. Edit to add: video linked.

I have and like the flip stops on many of my cams.

Same goes for the STRING M it seems: AAC Publications - Fall on Rock, Equipment Failure Due to Mis-use, West Virginia, New River Gorge, Kaymoor 

By all means support Brent, seems like a cool guy. I’ve used rubber bands to achieve the same thing and it’s worked great for a dirtbag fix. I actually even used Brent’s video of how to put on the flip stops but used a rubber band instead, but yeah not on alpines

I bought a bunch of flip stops this spring and have liked them pretty well so far.  I've mostly used them cragging, but have also used them on a handful of multiipitches.  They mash the sling a lot, so if that triggers any lurking ocd tendencies, that might be a negative.  Otherwise they've been awesome in all applications.  The one other possible negative is when I've used my cams for fixed line rigging, a handful times the flipstop has gotten a bit beat up from clipping in on top of them.  If you're using them that way a lot, that might be a longevity issue long term.