Pros: The only fans I really use in builds nowadays. Cheap, uniform, and good cfm, along with very bright LED's.

Cons: None, it's a fan.

Pros: Easy to use, ergonomic. Haven't had the squeaking yet but will update if it does occur. The software that comes with it is pretty useful and the ability to switch DPI on the fly is very nice, especially for a gamer where quicker turning is necesary.

Cons: So many buttons. Accidentally hit multiple of them multiple times.

Overall Review: Paid for one, but got two. Now I have a replacement if one breaks :D