Are the affixed sling mount end plates significantly more durable than their QD counterparts?  Has anyone ever had any experiences with the QD slings pulling loose from the end plate sockets with hard use or significant force?  

Most durable sling mount end plates?

I have a steel spike's endplate. I've been using it for months now and no signs of wear. Just pick one made of steel if you choose a QD endplate

I have a IWC and a Fortis QD endplate and had zero issues with either so far.  I use a Magpul Gen 2 MS-3 sling...

I've got a steel Noveske QD end plate. Never had a single issue. Also had an aluminum one with sling loops for mash hooks that got chewed to shit within 2 months of a deployment, another steel fixed point that had vertical slots for the sling itself that got busted to hell in 3 months (not deployed), and a Magpul ASAP which I just plain didn't like. I've put them all through considerable abuse

Noveske and IWC are the 2 I really like.  Haven't had issues with either one.

I have a BCM end plate on my lower, I can't collapse the stock all the way and I can't take out the sling with the stock in "position 1" (1 notch back from fully closed). Have not have any issue with it twisting (not sure if anti-rotational or just has not been an issue for me). I use a Magpul MS1 sling body with dual QD ends on it (MS4).

In my opinion, this is better due to (at least my preconceived) staking the lock nut and using a bit of locktite to prevent it from backing out. It also does not add anymore weight (ounces = pounds, pounds = pain as the old saying goes). Like I said, I could be wrong on this point but it is why I chose to get an end plate versus an add-on mount.

They're all "anti-rotational". The reciever extension keeps it from going a full 360°.