Android phones have a ton of nasty issues, especially with battery swelling and damaging phone's internals.
http://www.phonearena.com/news/Samsung-acknowledges-Galaxy-S4-swelling-battery-issue-offers-free-replacements_id48352http://www.geekzone.co.nz/forums.asp?forumid=97&topicid=138500 He said that his one store alone had a waiting list of over 20 people waiting for faulty battery replacements, and he hadn't seen a spare battery for the SGS4 for ages. He suggested strongly that it was likely the other Chch TRS stores had similar waiting lists.
never seen such problems with IPhone.