Having its own product adopted by users because of it efficiency, and not because of some "illegal" practices (from the point of view of European laws relying on competition, etc) is the most important.
Kaspersky asked Russia and the European Union to investigate Microsoft’s Windows 10 practices that encourage (and sometimes force) users to replace third-party antivirus with Windows Defender
=> All depend on the practices that MS really uses. If nothing bad : cool.
I will personally wait the result, before slashing Kaspersky or another company.