There is no sensible way to say either is technically “better” than the other. They are both modern development environments.
When talking about developing for Android vs iOS, the critical difference is not usually technical, but business. On Android you can develop outside of the App Store model and the restrictions on being in the Store are generally considered less onerous. On iPhone/iPad, you may only make applications available through iTunes.
This makes iOS developers dependent on Apple's permission to ship applications, and there have been a number of high profile complaints from authors who have had their application's approval delayed or denied on what seem to be spurious and capricious grounds. This has made a number of developers critical of Apple, and supportive of a more open development platform. They see Android as the best chance of unseating Apple's current dominance of the smartphone market, which is why advocates push Android as ‘a better future’.
(And maybe they're right.)