Another Mullvad user here. Generally happy, but the Windows and Android apps are somewhat buggy.

Every couple of weeks I have to reinstall the Windows app because it's failing to update, and the Android app started eating my battery recently (used 46% of a full charge yesterday after some hours of internet browsing).

In their defense their support has always been amazing when I contacted them about it, and the Android issue could be manufacturer's fault, since OnePlus is known for its shenanigans.

I'll continue with Mullvad for the foreseeable future.