I currently have a Samsung Epic. I’ve had it for probably about a year and it does the job just fine. It’s nice enough. I never wanted an iPhone because I’ve had Sprint since 2002 and, frankly, I have a pretty good plan/rate. Everyone has complaints here and there about their phone provider, but I always have service, I rarely drop calls and my data and texts are unlimited. Sprint didn’t have the iPhone until recently and my desire to stay with Sprint out weighed my desire to get the iPhone. Now that the iPhone is a real option for me, there seem to be a lot of pros for the iPhone and not a lot of cons.
One thing I thought would be a pro for the Epic is it has a slide out keyboard, but also a touch keyboard. In all the time I’ve had the Epic, I’ve probably used the keyboard 10 times. Max. Other than than (and that’s not really even a pro), I’m sort of at a loss.
As for the iPhone, here is the list of pros I have compiled:
– you can group text (on my Android, I get group texts from iPhone users, but I can’t reply to everyone – only the sender)
– apps come out for the iPhone first (Instagram – which came out on Android yesterday, but isn’t working as well for me as it does on my iPad – specifically, it’s saying the pictures my phone takes are too small; Pinterest – can’t get it on Android)
– can take screenshots of the phone
– can facetime with other iphones or ipads (great for families with small children/grandparents)
I know it’s not a really long list, but it’s long enough to make a difference to me. I’ll venture to say eventually I’m going to make the switch.
Predictably Unoriginal 
Pretty uneven to compare the 2. The Epic is considered a dinosaur now for Android. Android 4.0 pretty much soled all your issues. Not to mention I had video chat calling on my Evo 4G before face-time ever came out. Also, iphone facetime only works on wifi. I would wait for the samsung galaxy s 3 and the iphone 5 to come out this summer for a true comparison. :)