About 2 wks ago I gave my Dad my iPhone 5 and took his 4 for the time being since I know I will be getting the 6.
The experience with the 4 since I've had it has been terrible. It is slow as hell to the point at times I won't even bother using it. Apps seem to take forever to open and internet browsing is slow. It could be because I'm comparing it to the iPhone 5 whereas if I wasn't using the 5 and stuck with the 4 I wouldn't notice or care, but nonetheless I can't wait for the 6! And I will enjoy it that much more since I've been using the slow, small screen and chubby iPhone 4.