[jayvanguard]

OS compatibility layers never work well. I expect this to fail within a couple of years max. It'll be used to convince people to do a quick one-time port of their iOS apps over. Microsoft won't be able to keep it with Apple's API changes so it will always be behind and crappy.

[lukeh]

They don't have a good reputation, do they. But, it depends on how much engineering resource Microsoft dedicate (and of course, how quickly Apple evolve their APIs/applications make use of them).