I know this is getting a little picky, but I shot 8 stages of PCC at our last USPSA match. Lots of running and gunning. Had a blast. 220+ rounds.
I also got some skin abrasion on my weak hand at the thumb knuckle holding my Magpul VFG. Those M-LoK slots have sharp edges.
Just added a M-Lok Type 1 rail cover to those lower open slots. Wow, what a difference in feel. $15 well spent.