Let’s study the pros and cons.
Apple have the sanest API/platform evolution and the best IDE. I have hated IDEs ever since they first came out in the 90s. Xcode circa 3.2 is the first IDE I will deign to use and frankly I find it amazing. Many reviews criticized Xcode for being crappy compared to Visual Studio and I could not fathom why so many people said the same thing, when I found Xcode’s auto-completion, etc… to be superior to Visual Studio’s. I later realized it wasn’t until Xcode 3.2 that Apple finally got it right. Visual Studio would have been fine, but that blasted PoS crashes on me even when I’m just doing something as innocuous as tweaking color syntax highlighting. As for Eclipse (what Android developers use), it is certainly supposed to have everything but the kitchen sink, but my impression is that it is even less elegant than Visual Studio and the UI exhibits the lag so typical of Java apps (at least this was how I remember it when using it for Flex).
Microsoft’s .Net CLR is by far the most advanced platform to program under and waaaaay ahead of Objective-C. Objective-C was the most advanced platform by far back when NeXT was just introduced (compared to the Stone Age Win32/MFC and pre-Stone Age OS 8/9 development tools) and this is what makes it still (barely) bearable to develop for today. But someone who’s used to programming under, say, Python or Ruby (both available under .NET) is going to kick, swear, and scream when taken back to the Bronze Age of Objective-C programming. C# programmers (Iron Age ;-D) might not kick or scream as much but will still definitely find plenty to cuss about.
On the other hand, if Windows 8 action games will still need to be coded in C++, I think I’ll happily use Objective-C first and wait for the hardware to catch up to the CLR before venturing into games for the Metro environment. C++ is lipstick on a pig, garish and hideous, whereas Objective-C’s minimalist additions to C syntax together with its sanely designed runtime and library, are actually a significant enhancement over C even if still far from the convenience of its VM-based competitors – C#, Ruby, Python, etc…