"Ein user hats im Reddit recht schön zusammen gefasst:
No SLI/Crossfire,
Windows 10 store download is buggy,
No refund policy explained,
Vsync is always on,
Always borderless fullscreen,
Game files are protected,
Can't launch it via the exe (So adding it as a non steam game will not work)
No fps/hardware monitor software works with it,
You need to take control of the folder as admin if you want access to the files
Mouse software which lets you create custom binds for each game doesn't work
Say bye to using sweetfx and mods
No Overlays at all - so no OBS / recording, EVGA Precision, FPS counters, Steam Overlay
[...]
No Steam Controller / Steam Link functionality
No Injectors
No Freesync (since no fullscreen) & reduced gsync performance "