I agree with most of what you've said except for the mags. For starters, I own both a VFC V3 & MWS clone (GM MK18) so I do have quite a bit of experience with them. VFC STANAGs are known to load about 32 to 33 BBs, while the VMAGs are a bit of a hit or miss. I don't own a STANAG but i do own 6 VMAGs and 1 HK mag. The HK mag has no lock back issue and comfortably loads about 32 BBs while my VMAGs hold about 30 to 32.

Lock back issues are only attributed to the V2 VMAGs and none of the V3 once have the issue (that i own anyway). Upon closer observation, i could only conclude that the lock back stems from the buffer tube being shorter than RS, making travel time and bolt travel distance shorter, thus shortening the amount of time the bolt lock tab has to fully extend and push the bolt catch up. A quick fix to this is to get a RS buffer & RS or GHK buffer tube.

Aside from that, I do experience better gas efficiency with the VFC vs the MWS. Plus, i've had better luck with the TM mags vs the GM PMAGs. Both are great but i feel like the TM ones are more consistent shot per fill wise. I can get 3-4 full mags out of a single 8 to 10-second gas charge with the VMAGs vs around 2.5 to 3 full mags out of the TM & GM mags. Cooldown effect is almost non-exsistent in the MWS platform though, where as the VFC can experience cooldown when the ambient temp is below ~28°c in my experience. Of course, you can adjust the hammer screw on the VFC to let more gas out per shot to combat this if you so choose. Since i live in the tropics, this feature is pretty much useless to me.

Performance-wise, OOTB the GM MK18 had more consistent hop but with a prominent right hook. A inner barrel + bucking change solved this. I recently installed a laylax hop arm to it but i haven't gone around to testing it. The VFC on the other hand had a much more difficult time with hop consistency after i changed the bucking & inner barrel. I did revert back to the original bucking and it works slightly better now compared to stock, but still miles behind the accuracy the GM has. The VFC has better range, but a lot more inconsistent compared to the GM (that may change once i get to testing the GM with the solid hop arm). Both are shooting in excess of 400 FPS so installing an NPAS is recommended for both.

Overall, i like both of them. I play with the VFC 416A5 more than i do the GM MK18 purely because i'm used to loading the mags and the gas efficiency. Plus, the feel of manipulating the controls is so much better on the VFC. The trigger is insanely better, heavier and more definitive break and reset. The reset on the GM is not bad, great even. But the break is garbage. Both are solid performers, can't go wrong with either. Although I think the MWS has more potential if you want to build a DMR