The python support for Android is pretty good, but still under development. You can do things that a scripting language can but not the stuff that Python as a OO language can.
Example:- When you go through the api reference here, you can see that one can write scripts to do basic to complex tasks, but, in a restrictive way. You can never build full blown apps, and even if you do, it will always be slow because the SLA4 is just another layer on top of few other layers in the Android hierarchy. There have been a lot of fun stuff that has been done using Python scripting, example: http://www.wired.com/gadgetlab/2010/07/nexus-one-phone-rides-a-rocket-up-28000-feet/#ixzz0v7LFT7ay (A bit over-board and crazy, but awesome nonetheless.)
I don't have much experience on an IPhone to pass on such comments. But, an IPhone is expensive. You can always get a used Nexus phone and do all kinds of Python hacking/scripting. All depends on your budget and your need.
That is all.