Which one should I buy ? iPod 4 or iPod 5?

[StyloxX]

Hey, I collected money enough to buy iPod 4 . Then I checked out a catalog and got to know there's a new generation of iPod, iPod5.
They say it has more features. I checked them out and there were four more features like Siri, better camera quality and others
My question is, is iPod 5 reliable ? or is it not suitable to buy? I have enough money to buy iPod 5 too. but I want your opinions . Has any one of you used it? If so, how is it?
I know we can enjoy all the things on iPod5 on iPod 4 too , but now I am thinking to buy 5 th generation. Do you think I should buy it? I am afraid bcuz I have seen some companies release their better versions of devices and they are just flop.

Anyway, what is Siri?

Please Please answer , I have to buy it tonight