Likely. The other way to look at it is that many of the apps that are present in Windows phone app catalog are the ones where Microsoft convinced the app developer to write for the platform specifically. Now if that strategy is used then its obvious that Microsoft would have courted the top quality apps rather than going after poor quality ones.
Eventually, they'll all have tons of apps, both good and bad. So, for me, #1 will go to the app store with the best app discovery service.