I just received my Magpul M-lok QD mount today, and I have to say I'm impressed. It is VERY small, super lightweight (feels like nothing is even in your hand), mounts up solid, and (gasp) is rotation limited. Very nice piece. I ordered one because I'm less than impressed with my "built in" ALG M-lok 13" FF rail's QD (no support as it's not a "socket", will rotate if pressure is put on, and quite honestly, I wouldn't trust that QD hole for even casual use. It's worthless and I'm not sure why ALG even bothered to put the hole there).
Back to the MP mount.... it mounts into a single M-lok slot, so it can be mounted far forward (which I prefer). I DO wish it was melonited steel (as some of their other products), but instead it's aluminum. I guess that's a blessing and a curse. As said, being aluminum, and tiny, it is ULTRA light weight. How strong it is only time will tell, but it is a good socket with substantial surround, so I'll have faith in it unless proven otherwise. And for $19 shipped (Aim Surplus).... well done Magpul!

I have the same hand guard as you and the built in QD sockets are not giving me any concern.
In fact my swivels lock in tighter with less wobble than other "full socket" designs I have.

The tolerances of the swivel it's self do come in to play and I am using ALG's own premium design.
I have had fit issues in the past with other swivels, even ones supplied on slings made by what some
would call top of the line manufacturers.

I have only been using the hand guard for a month but so far so good.

Yes, I love the handguard, just not the QD hole design. I just don't trust it as it has no support socket. I'm much more confident in the Magpul QD socket.