I've got the GS3, which is the same size as the GS4 only slightly thicker. I like it. The size took some getting used to, but I'm used to it. Battery life seems substantially better than my friends who have iphones. I can unplug at 830 a.m., and when I plug it in at midnight or so it's at about 50%. I don't spend a lot of time watching videos and such though.
I like the android platform for a lot of reasons. I like that everything syncs to my gmail account. If I destroy the phone or get a new one, all I have to do is sign in on the new one and all of my contacts, emails, pictures, etc are all there again. I like the replaceable battery (I can go on a 3-4 day motorcycle ride and just bring a spare charged battery and make it back with some battery life remaining). I like the screen that doesn't break when you look at it wrong. I like that I can split screen 2 applications at once ( i.e. I don't have to interrupt the Blurred Lines video to respond to a text or to check an incoming email.)
Iphones are good for what they are. Fashionable accessories that are dumbed down for the common user. Anybody can pick up an iphone and use it, and if they don't care about signal reception or having cutting edge technology (screen tech, camera tech, processing power etc), then it works great. My mother is a perfect candidate for an iphone for example as all she would use it for is to play words with friends and make emergency calls, but I think she would hate my GS3.
The iphone is actually the only piece of apple hardware I don't own at this point, and I hate them all pretty much equally (to be fair, I actually like my Macbook air). I don't have an apple TV either I guess. Overall, I just don't like the lack of reliability of them, how slow they are, and Apple products might as well be the Westboro Baptist Church when it comes to accepting and working with other technology. Unless the iphone 6GSc comes out can emit some sort of wavelength that simultaneously cooks bacon and zaps the crazy out of women, I don't think I'll ever pick one up.