I hate the arguments over which language is good for front-end....just like I hate the non-sense arguments over indentation/space in python, emacs/VI in Linux.....there's no general consensus.
Android is good, and I suggest inexperienced students to do some apps on Android platform as projects to practice programming, but I doubt the prospect of being a professional Android developer. By the way, iOS developers make a substantial amount of money, because Apple users tend to pay for their apps and are more likely to pay for service.