While some articles out there are busy making noise on how much Android is fragmented, I haven't seen a lot of noise about the latest http://developer.android.com/about/dashboards/index.html#Platform
update: Gingerbread is down to 1/4th and ICS + JB is up to almost 3/4th.
Let that sink a moment.
It means if you want to reach 75% of your potential customers, you can safely use API 15 and +, which has all the modern bells & whistles. And if you want to reach 97.8% of your potential customers, all you need is use a minSdk of API 10, which combined with the support-v4 and the appcompat-v7 libs gives you all
the benefits of ICS or JB modern UIs with fragments, animations, action bar and whatnot without having to think too much about multiple API levels.
There are quite a few new APIs in ICS and JB (listed at http://developer.android.com/about/versions/index.html
) but let's be real: a vast majority of apps and games probably can do without them and make them conditional, which is trivial to do at runtime.
Welcome the diversity, forget the fragmentation.