What would I really be missing from switching iPhone over to the S4?

I'm probably going to switch from iPhone 4 to samsung S4 due to I needed more memory and the S4 looks good and I saw on reviews that its better than the iphone 5. The S4 can have added memory and other features like the eyes thing and the sensor. What would I be missing if I made the switch to the S4 that it wouldn't have and the iPhone would? And what does the S4 have that the iPhone wouldn't have? Pros and cons of switching to the S4?

" the S4 looks good and I saw on reviews that its better than the iphone 5"

There are advantages to each that make either phone better depending on the owner.

"What would I be missing if I made the switch to the S4 that it wouldn't have and the iPhone would?"

iOS apps come to mind.

"what does the S4 have that the iPhone wouldn't have?"

I'm pretty sure that the battery on an S4 can be removed - though you should check that out yourself.

The point of removable batteries is that 1) if the battery really dies, you don't have to replace the whole phone (which is why Android phone makers seem to be moving in that very direction). 2) You might be facing a situation in which you won't know when you'll be able to charge your phone. This happened to many people on the east coast last Fall when Hurricane Sandy hit. I was in the dark for less than 2 days, and I was lucky. I was also lucky because I had a Samsung Reality which allows battery swapping. I also had batteries from 2 other Reality phones that my kids had had but upgraded from. Therefore, by the time the storm hit our area, I had 3 fully-charged batteries.

You would be missing better app and game selection and significantly better build quality

It's poetry: it's all prose ( this is the ONLY play on words LEGAL would let me use!)

The S4 is off the charts as far as Apple goes, as in term of Apple IP4 to IP5 is just to the SGS II.

There are no cons quite simply put the SGS II is superior to the IP5.iPhones play catchup and what appears on an iPhone had already been released.
The S IV has scored the highest benchmark score geekbench 2 for a phone ever

There are so many phones better than the IP5 its comparison to the S4 is just on cost
Also removable batteries offer soft reset or battery pull

You'd be gaining a lot more than you'd be losing.

You'd lose the larger App Store on iOS. You'd lose any apple apps, like Facetime or the like. You'd lose the iPhone's aluminum build (S4 is plastic).

However, you'd gain the S4's superior hardware, it's larger screen, and all the benefits that Android and TouchWiz have to offer.