I upgraded to an iPhone 5 from a 3 so it was a huge leap and totally worth it! I love the 5, and there is not necessarily another one coming out for a long while yet, so I wouln't wait around in the hope that the 5S or 6 will be here anytime soon.
I find the battery life to be ok, and it charges super super quick! This iPhone isn't perfect, and actually can get scratches and personally i haven't got on well with the maps but other than that i'd say its speedy, and so much more up to date than the other iphones, like for example being able to use 4G. It's the little details like panaoramic camera and the do not disturb feature that I really like.