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?

How to Get Siri To Call Me By My Name?

So I Just Got My iPhone 4S Today, And I Want Siri To Call Me By My Name, But Everytime I Say "Siri, From Now On Call Me… " Or "Siri Call Me… " She Always Says "Sorry, … Can't Be Found In Your Contact List".

Factory Unlocked but No Service: iPhone 4?

Here's my specs…
iPhone 4 (AT&T) - 16GB
iOS @ 5.1.1
Untethered Jailbreak
I brought my iPhone 4 to my favorite Unlocker and he "Factory Unlocked" my iPhone 4. I picked it up the next day, and I inserted my T-Mobile SIM Card (which size IS correct) and the iPhone says "No Service". I hear many things such as restoring the iPhone and such, but wouldn't that ruin the jailbreak and get rid of the unlock?
If you know what to do, can you please tell me with a good description?

Why won't my iPhone 4S stay connected to Wi-Fi?

Every time I'm connected to Wi-Fi and then lock my screen the Wi-Fi isn't connected anymore. So then I have to go to setting and reconnect every time. How can I stay connected to Wi-Fi even when I lock my screen.

Why isn't my sound working on the iPhone app snapchat? - 1

I just updated the new snapchat and we can send videos BUT my sound isn't working and i can't hear ANYTHING while others can.i've restarted the app and my phone and i can only hear through my headphones not through my speaker and my speaker works too. Any other suggestions?