Android is way more customizable. If you look hard enough you'll be able to find an app to fill pretty much any of your needs. However, if your Iphone is doing everything you want it to (are you interested in anything other than texting? Do you really need to upgrade? You could probably get a 4s for free) than why change from something thats working for. If it ain't broke don't fix.
However, this is an android forum so recommending an Iphone probably makes as much sense to everyone here as recommending a Windows phone!