I feel sorry for those, likely new to the iPhone, users who go for an 8GB iPhone.
It's far too little memory for iOS7.
Looking at the 8GB iPhone4S at the Apple retail store, I see about 1GB left for user Apps and data.
Apple; this is not the way to gain happy iPhone users.
BTW my 16GB iPhone 4 runs very well with iOS7, which I like, but I had to delete quite a few files to upgrade from iOS5 to iOS7.