Why the Mac App Store Sucks
Some of these aspects will certainly apply to the Windows Store, too, other aspects of the criticism ultimately depend on Microsoft's specific implementation. But for paid apps, keep this in mind:
On the technical side of things, and I assume it's true for future Windows Store Win32 apps as well since they run in a sandboxed/virtual environment:
So people who expect
every Windows program to appear in the Store and thus have it work flawlessly across all Windows devices may be in for a (negative) surprise. As a Mac user, I get the Apple office suite, Twitter, Reeder, Evernote (side note: they've just pushed update 6.0.9 to the Mac App Store today, while the non-MAS-app is at 6.0.10), Microsoft Remote Desktop and Condense through the App Store, everything else - Dropbox, Spotify, Steam, Origin, Cisco AnyConnect, VLC, Adium, Chrome and more - I still have to download separately. Which is disappointing because the concept of one store on the desktop is good for the users as all the apps you get through it are kept up to date, without all these different application-specific update mechanism that usually suck.
But let's see how Microsoft is going to tackle all of this. One advantage of the Windows Store over the Mac App Store is certainly the wide range of devices you can target with one app, compared to just Macs with the Mac App Store. Whether or not that makes up for the downsides then remains to be seen.