s4. have one and it's amazing. have an iphone 5 for work and aside from siri iphones are lacking big time. if clash of clans was on droid i would drop it altogether.
I've had an iPhone for the longest time and bought subsequent generations but stopped at iP4S. It's a nice UI that's it imo just a Unix flavored candy and I still hate the battery. I changed my phone finally to a Galaxy and highly recommend it.