Android vs iOS, what phone is best for me?

[Stu]

wow, OK here we go.

you seem to be budget minded.....and you need an unlocked GSM phone.
so i am going to suggest the Google Nexus 5.....its $350 off contract, unlocked (that is a phenominal price...iPhone 5S's are $650 off contract)
its a top end phone and runs the latest version of android and will run the latest version for at least 2 years.
next up is the Motorola Moto G....its $180 off contract, has some decent specs, a nice screen and runs the latest version of android.

as for the older phone, as long as it is 4.0 or later, you should be fine. more and more apps are 4.0 and later only. but if you are running 2.3 or older, you may have a hard time finding apps that work.