Pros: priced right

Cons: noisier than I had hoped for and seem unbalanced.

Pros: It spins quiet

Cons: None

Pros: I have two of these in my case acting as bottom intakes. At 12V, they pull in a lot of air, even more than most dedicated air flow fans out there.
These fans are quite cheap considering these are nothing more than black Vipers. I suspect that this fan may soon be discontinued, which is a shame, so take advantage of the price drop while you can.

Cons: These fans aren't noisy, but the air coming out of them is. There is a weird wind "roar" that starts to appear once you hit 9V, which only gets louder and more audible at a distance. With two of them working next to each other at full speed, the air coming from them make an off-beat fluctuating noise that might annoy some.

Other Thoughts: Like the title says, these fans are Rosewill-branded Akasa Vipers, except they ditched the yellow fan blades for a much more neutral black.
I've yet to try these as radiator fans, but the 120mm Akasa Vipers do have a pretty good reputation among water-cooling enthusiasts. I think the 140mm falls short of the 120mm's cooling power due to its lower static pressure rating, but it's much quieter than Corsair SP140 fans at full speed. An opera singer stepping on a LEGO as he's leaving the shower is quieter than a Corsair SP140.

Pros: I see people complaining about the loudness of this fan. That is because if you want it to it will move as much air as a box fan (well... kinda.) There is a reason it is a 4 pin fan with PWM. I plugged it into my ASUS Z97-E with Fan Xpert 3 and turned it down to 20% unless it gets warm and even at 20% it does a really nice and even quiet job. At 100% it IS really loud and moves a TON of air.

Cons: Took me a little bit to adjust the speeds to where they need to be.

Other Thoughts: I have two of them and they keep my case cool and quiet at 20%-50% speed and can ramp up to do the job when needed.

Pros: Move a lot of air
Quiet
FD Bearing
PWM control
Nice long braided cable
Rubber isolators are a nice touch

Cons: Expensive if you don't catch them on sale

Other Thoughts: I have 6 of these in my case now. Look great, the price is right and the rubber mount tabs work great. If you are careful you can re-use, if not then if you are like me you have a ton of computer fan screws lying around. I don't plan on having to move any of these any time soon though. Brand new Fractal case and build and a battery of these fans keep everything flowing great.

Pros: Great price and quality

Cons: None

Pros: Moves a lot of air and is Very quite......Grate Fan...

George

Cons: None at All.......

Other Thoughts: I like it.

Pros: Replaced my dead stock corsair fan for my H90 liquid cooler. Incomprehensibly quieter...actually, I can't hear it at all. CPU running about 3 degrees Celsius warmer on average over stock (was averaging 29 with stock before it died and is now averaging 32). I still count this as a pro though for the significant noise improvement.

Cons: None

Other Thoughts: The nominal temperature increase won't be a con for anyone unless you've got a custom loop and are maxing out the over lock on your system...but then you shouldn't be looking at this for that anyways.

Pros: Good CFM and static pressure
Fairly quiet but makes a weird sound (see other thoughts)

Cons: The mounting pieces that come with it are garbage, they're flimsy pieces of rubber that rip quickly and don't do much of any good.
Has a weird sound it gives off that I've never heard from a fan before (probably from the bent blades).

Other Thoughts: I got this as an intake fan with a silverstone ultra thin fan filter. The static pressure from this work fantastic with the filter and has put my case into a positive air pressure inside the case (less dust and more fresh air getting into the case, so lower temps overall).

The fan itself makes the weirdest sound that I can't identify the cause of nor explain the noise itself. To say the least it's worrisome, and isn't noticeable from more than a few feet away. I only noticed it after installing (with the side panel off) and after putting my head up close to the case to examine that it was working correctly. The noise doesn't get worse as the RPM gets higher; it in fact gets drowned out by the sound of the air pushing through the fan, which is significantly loud. Despite the specs saying it goes up to 1300 RPM, my case manages to get it up to near 2000 RPM which gets loud but not unbearable. I'm not sure if pushing past the rated 1300 RPM is safe, so I don't recommend it.

Pros: Very quiet fan with strong air-movement. If your not into LED displays, then this is the 140mm fan for You. It move air like the ol' Cooler Master 120mm with bent-blades. Bent-blade fans have good static pressure for heatsinks and radiators.

Cons: No LEDs.

Other Thoughts: Makes an execellent case fan! Very quiet throughout all speeds.