First about this:
However, one of the things that plagued the popularity of J2ME was that the phones were very different in supported features and screen size. The IPhone is great in this regard as it's only 1 device that a developer must troubleshoot and develop against - even though it's a closed platform.
Yes that is a problem for J2ME, but in Android it is not really a problem, you just need some extra time to make another XML layout design for the said screen and there it goes!
What are your thoughts regarding developing for Android w.r.t. the differences in devices that may exist in the near future.
Android will be everywhere just like Java! , i think the differences would be the phone manufacturers and their supporting hardware if they will permit or not, and ofcourse every country carriers will be a big problem if they will permit them or not (the features android have).
Also, how would you compare the development and deployment of apps between the Android and IPhone platforms?
As what Mark said, me too haven't tried coding in iPhone, but i knew people doing it and i've seen the code structure, i guess it is more c++ programmers phone , and Android is more of a Java programmers phone!
also about the Title
Thread, iPhone and Android will always be different, and they will always stay as competitors, the problem now for each of them is that Developers and End-Users have now options whether to work proprietary or work openly?