and rooting (jailbreaking equivalent) the Android would give the Android even more expanded functionality. 3G Hotspot on the fly, customize every aspect of the Android OS and its UI, tweak existing applications,
Can all be easily done on the iPhone.
overclock your phone, or underVOLT your phone for even better battery life. The undervolting/overclocking cannot be done with any iPhone, past and present. In essence, I am able to overclock my Droid X to 1.35 Ghz, with AMPLE battery life to support that speed increase.
Why would I want to overclock or undervolt my iPhone 4? It's as quick as can be and battery life is good. Not to mention I wouldn't want to risk hardware failure from overclocking. It's not like you can just add a better cooling system like a desktop. And combined with undervolting can make things more unstable. Sure things might be just fine for awhile, until one day.... CRASH!!
If one is all about enhanced tweaking, Android is clearly the way to go.
And why isn't the iPhone the way to go for tweaking ...
How about windows phone 7, that looks better than android to me right now. Although there are a lot of missing apps right now.
The whole SD card situation really bothers me about WM7.