I'm not a hardcore programmer (PHP/Perl... lite stuff), but I thought it would be fun to try out mobile app development. I happened to have an iPhone, mac, etc... so I started there. Even with the books and intro material, I found it very difficult to get into. My C and similar is very rusty, so that was part of the problem. For the heck of it, I tried android and that was MUCH easier to get into. My Java was never great, but better than my C - which again - helped. All in all, I much more enjoyed the experience of working on the Android platform because it tended to have lower barriers to entry (less hardware, less software, etc), be easier (Java _is_ a simpler language) and be fun.
Though get a good book for android. Last I checked, the official docs online from Google were for like 1.0-1.5 and we're on 2.2. In short, horribly out of date (usable in some cases, but out of date).