I've honestly never heard any of those kind of problems with the S4. There is absolutely no lag on my wife's s4, I can't speak about the SD card cause she doesn't have one, but the dropping thing. I've tossed it across the the yard into the drive way (we have the full replacement insurance on it) just to see and not a scratch. Maybe it was the case you got, she has the speck back cover and an invisible shield screen protector.

Sucks to hear you had a bad experience. Although, I do think you're a fan boy/girl haha. Everyone I've heard say anything about iOS 7 is either asking why it sucks or explaining why it sucks.

Sent from my SAMSUNG-SGH-I747 using Tapatalk 4