I origiinally didn't care for the MS3. My biggest complaint is that the new fastener is not a snapshackle. This does two things:
* It looses its quick detach under load functionality. Yes, the new snap kind of works but the original snapshackle was much easier (didn't require fine motor skills) to detach. Some complain that the MS2 snapshackle disengaged accidentally –– I never experienced this.
* I think the biggest problem with it is that it lies on a different axis than the snapshackle. That is –– the snapshackle connects in a plane perpendicular to the ring on the ASAP plate which doesn't put any twisting force on the sling. The MS3's connector locks on and tries to turn the ASAP plate ring onto the same plane as it causing the sling to twist a bit. This makes performing lateral transitions (at least the way the old Magpul Dynamcis guys used to teach it) difficult. This also makes techniques like trapping the rifle under the sling difficult.
Obviously, one of the benefits of the MS3 is the wider webbing. I've found that removing the snapshackle from an MS2 and transplanting it to an MS3 gives me the best of both worlds.
If I'm the first to do this, I name it the MS2.5.