Pros: -Good airflow. I bought two of them, one for the front of the case to pull in air and one for the back to push air out.
-Quiet enough, definitely a much better sound than a fan with bad bearings.

Cons: -For some people, these are too loud, but with a headset on or speakers playing music or game noise, you can't really tell, so no egg off for this one.

Other Thoughts: I bought these to replace a fan that was starting to break and installed the second fan to replace the other so that I had a consistent airflow and no problems with RPM. You have to create the threads into the fans, which with a good enough screwdriver, it shouldn't be too hard, just make sure to use the right size. For full price I am sure you can get a better, quieter fan, but I got these for $5 each and they are easily worth that.

Pros: Great price
Comes with 4 tiny screws for mounting. 3-4 pin power cable adaptor. Specs 120x120x25 mm, 2000RPM,29.28db(A), 12V 74.48 CFM
I use at around 1700 rpms and I can't tell if the faint noise I hear is from the stock case fan or this. Very quite as I can hear my Full size freezer at the back of my basement over this fan that is located at the front of my basement/man cave/den.
System stays cool, fan works and blue LED makes my case look cool.

Cons: Big con, no arrows on side to show airflow, only arrow on front to show clockwise/counterclockwise direction. Took about 20 minutes of internet research to verify that air flows towards the mount arm bracket with the wiring for the motor behind it.
Power up verifies that the air flows towards the engine mount arm and that I installed it correctly as I wanted it for front intake.

Comes with 4 tiny screws for mounting (I guess if you screw from back side of case holes into fan it might work), lucky my case came with the long screws that feed though the front and back holes of fan prior to case holes for a more rugged connection. This permitted me to use my screw driver from the front of case with little fear of touching the motherboard/inside electronics.

Other Thoughts: I want another to fill out the 2 120mm fans supported on the front of the case.
I will buy again when my wife approves an increase in my personal IT budget.
I will have to pick up some larger screws as I don't think I want to try to make the tiny screws work.

Pros: Moves a lot of air
LEDs are bright

Cons: Quite loud at full speed. Decent at lower speeds.

Pros: I like the lighted fans. this looks nice
It does seem to move lots of air, so it does what it's supposed to just fine.
Was worth a healthy discount sale price.

Cons: At full speed, 29 DB is not very quiet these days
You could buy better -for the full asking price you could get a VERY quiet fan.

Other Thoughts: I am happy with these at sale price and speed modified by my mobo...slower,quieter.
Have not owned this model long, don't know how long they last.

Pros: Awesome, perfect size, very bright

Cons: The screws wouldn't go in the holes, they are very hard to turn.

Other Thoughts: I would recommend.

Pros: Blue LEDs are nice
Nice airflow
Wasn't too much of a pain to install
Nice and quiet when not on full blast

Cons: at 100% the fan does get a little noisy, with my speakers up and when submersed in action I don't notice it, but when the action settles down it's noticeable and honestly a little annoying
The holes on the fan aren't threaded, so you'll need to apply some force on the screwdriver when securing these to your case.

Other Thoughts: Given the chance I'd probably buy a different fan, but for $5 I really can't complain. The Blue LEDs are nice, the fan seems to move a good amount of air, it came with a power adapter, and it wasn't hard to install. The lack of threaded holes made it a little weird to install, but it wasn't too bad. I took away one egg because this fan isn't "silent" at 100%, although it is acceptable at lower RPMs (not noticeable). I bought this to go in my Rosewill case, and since it came with 5 Rosewill fans preinstalled including two blue LED fans, I figured this would compliment my system well. It does, but they aren't the same fans. If I'm listening I can hear this specific fan spinning. They aren't as quiet as the preinstalled Rosewill fans that came with my case. I have connected all fans to my case's built in fan controller switches. It's very basic, I get Low, Med, and High. On low and med this fan is great, on high it gets a little noisy. I really didn't think the noise could bother me, but it does slightly. Also, the blue LED changes in intensity slightly when changing levels. All in all it's a good fan for $5.

Pros: Used to be awesome fans for the money, now they are charging way to much for what it is.

Cons: I got them for 4.99. Kinda a ripoff now though. Was going to buy more then I saw that they raised the prices 100% and was like nope. Went with Corsair instead.

Pros: No issues, worked, its a fan

Cons: Didn't burn up and kill the cat?

Other Thoughts: Reliable, got a 2nd one

Pros: Very easy to setup
I don't think they're noisy at all
I bought two, and they've cooled my PC down by 30 degrees :)

Cons: None!

Other Thoughts: Would definitely buy again!

Pros: - Nice blue light
- High Airflow compared to the stock Cooler Master fans I had previously in my case.

Cons: - Loud on FULL RPMs, but I keep them at 40% most of the time, so not a real issue.