AirPort Extreme vs. AirPort Time Capsule... which one to get?

[The_Prodigy1982]

I'm configuring my iMac right now... but I'm not sure whether I should add the AirPort Extreme or the AirPort Time Capsule?

I like the product description of the AirPort Extreme, saying it delivers a WiFi signal up to 3x faster than normal.
However, I also like the backup functionality of the AirPort Time Capsule...

- Does the Time Capsule also give me that 3x faster WiFi??

 

[kch50428]

Only difference between the two is storage on the TimeCapsule model.