What's the difference between iPhone 4, 4s and 5?

I'm thinking of getting an iPhone but I'm not sure what one to get. I know that 4 doesn't have Siri, that 5 is longer and slimmer etc. Do they all have the same quality camera? Like they don't really seem that different

Added (1). Mainly what's the difference between 4 & 4s?

5 is not that different. It only has bigger screen and a LITTLE better processor.

Well the difference between them is that the iPhone 5 is a bit longer than the iPhone 4 and it has a better camera not that much better though and the iPhone 4 does have Siri and since the iPhone 5 is new it has more bugs and since its longer not all the apps have iPhone 5 support so i suggest the iPhone 4s

So first the iPhone 4 it has a good camera but I forgot what quality the iPhone 4 has a A3 chip so it runs a little slower than the iPhone 4s and 5 so it's ok the iPhone 4s has a A4 chip it has 720p recording you have Siri you also have notifications that alert you and stuff the iPhone 5 has siri a bigger screen it has a A5 chip it has 1080p recording you know how when Some pictures are bigger than the camera like you can i don't know how to explain it because I only know slot about iPods I really don't use iPhones

Iphone 4 has an A4 proccesor and 5MP camera
Iphone 4s has A5 proccesor and 8MP camera
Both iphone 4 and 4s have 3.5" screen
Iphone 5 has A6 processor and 8MP camera
4" screen
Get iphone 5 the design of the iphone 4 and 4s are 2 years old and when the 5s is out your gonna feel that you have an old iphone and will think about getting a new one

Hardware is alot better as you go up. Even 5 is made with aluminum backing on top it… Won't break even if dropped (although screen can obviously break so I woudln't recommend dropping it.

Get iphone 4s it is quite nice for today and it is more durable than 5. Iphone 4 is old news now. Get iphone 4s which is cheaper than iphone 5.