I'm in no way an expert but a lot of what Microsoft is touting is available in other browsers and different McAfee ENS modules. For instance, reputation-based browsing is a function of ENS Web Control. Chrome and Firefox both have hardened forks and plugins that provide click to run Flash and so forth. It seems like Microsoft is catching up with this release, not leading the pack. Out side of that it really seems like personal theories and preferences on single vendor use.
I do believe some of the "virtualization-based security" Microsoft provides are very interesting and should be working fine alongside McAfee products (credential guard, edge virtualization, …) . As far as I can see these do not require Windows defender to be active.