I was with Android for about five years and finally switched to iPhone.
If you are set on Android for whatever reason though, definitely the Oneplus... the price is great, and you don't have to bother rooting it to install custom ROMS, Cyanogenmod is a must with any Android phone...
BTW, even with lesser hardware the iPhone has proven to be more fluid/quicker in every action or app... so until that better hardware leaves a better benchmark, who cares.