Looks, its all down to what sort of experience you prefer.

If you want greater control over what can be done with your phone, go for Android. Just be aware that it has a number of quirks that are not easily resolved unless you're a techie. If you're willing to and know how to root it, you get a load of control over how your phone works.

And no, you don't lose updates by rooting. You just lose OFFICIAL updates but there's always custom roms like CyanogenMod and ParanoidAndroid that work quite well and have extra features to boot. More importantly - minus crapware like Samsung's Touchwiz.

If you want a phone that's easy to use and has a refined ecosystem, go for iPhone. However, I'm pretty sure you're well aware by now of just how restrictive the experience is as well - even when its jail-broken (which locks you out of future updates).  Most ordinary phone users will never notice this nor care even so its fine for them.

No doubt, the reason why you are even considering the switch in the first place is because you are already fed up with the restrictions, in which case you shouldn't be listening to all those stupid fanboys asking you to stay. But like I said, do your research and be aware of just what you are getting into either cos you might not like it.

Incidentally, anybody who says Android is laggy is a non-techie. Meh to them.

As for battery, KitKat is lightweight and has incredible standby time. If you're not on KitKat, too bad. If you are but your battery drains quickly, than you're doing something wrong. My phone uses <1% per hour on standby.