I think the better question would be:<p>What is best for your career given that the future is -- by definition -- not knowable and that the past and present are not necessarily indicative of the future?<p>After all, what is better today may not be better tomorrow and what is better tomorrow may not be better the day after. We live in a world where all technologies are in a state of decay, and our environment is rife with disruption and innovation.<p>Go deep (specialize) just enough to be unquestionably proficient, but not enough to be one of the world's foremost experts. Go broad (generalize) just enough to be learned (well-informed) in discordant technologies, but not enough to be omniscient (all-knowing). I call this type of a person a "genspec", a generalist-specialist.<p>For example:<p>1. It's more useful to learn functional programming, object-oriented programming, procedural programming, etc., than to learn e.g., 3 different object-oriented programming languages.<p>2. It's more useful to learn embedded development, mobile development, web development, etc., than to learn e.g., three different mobile development platforms.<p>3. It's more useful to learn e.g., 3 different OSs than to learn e.g., 3 different distributions of a single OS.<p>Optimize yourself for change, adaptability, and continual learning of many materially dissimilar topics.<p>That's what's best for your career.
I'm going to jump in here with an actual answer since I rarely see mobile development job posts where html5/lua is an acceptable alternative. iOS is currently more in demand and likely will be for the near future. Most companies go iOS first even if they plan on releasing for android, so even if you're skilled with bost it'll probably be easier to market yourself as an iOS developer.
Both. Learn both Objective-C AND Java. Learn cross platform development languages and techniques as well - javascript and Lua.<p>Whether you are looking for employment with someone else or starting your own company, having a broad set of skills is always valuable.
The one that you enjoy!<p>There is nothing worse than doing something you don't like, no matter how good you are paid for.<p>Do what you enjoy and will be a great for your career!
Why not develop cross-platform applications? As Zenst said, you could go the HTML5 route and use something like Phonegap. Personally, I'm a Corona SDK user. I can't comment on Phonegap, as I've never used it, but Corona makes it trivial to develop cross-platform apps written in Lua.
iOS. Here is my completely unscientific observations from a fairly wealthy place in the USA.. People see apple and assume that they will have to pay lots of [real money] to use those things. Apple has put a ridiculous amount of effort into making "Mac" and "iPhone" into luxury goods. Now all the trophy-wives and cougars have iPhones.<p>I want android or something more open to win. They don't have the brand though.