I also read many reviews of this product about the complains of this particular product or the corsair h series product. The fans are not so good. After I installed this product on my system I heard some rattling noise from one of its fan, and this noise only comes when its in its full throttle mode i.e 100% fan RPM, but when the RPM is lower than 98% the noise stops. I also saw in the reviews from other customes (not from amazon) having this same problem. Other than that its working perfectly, I have a i7 4790k processor boosted up to 4.8GHZ and at full load I am getting 65 - 69 (5hrs) degrees and 25-30 degrees idle.(Ambient Temp 21 degree)
Its mine first time experiencing Liquid cooling system. it was too big to me, because of the fans i had purchase new cabinate. Note : Some cabinate will provide you 2 fan ventilation but it comes in touch with motherboard so get more info of this product mesurements (WxH) then purchase cabinate according to it.
The cooler itself cools mind blowing. It keeps my 4.8GHz OCed 6700k well under 75 C The only thing that I really hate is that fan noise. you won't notice it if it is running on 40-50% but they become noisy if the speed goes above that.
This is a fantastic cooling solution. AIO coolers are all the rage right now and the H100i is a good example of this type of cooler. The included fans are quiet and the pump is barely audible when running in default mode. It can get pretty loud if you increase the pump and fan speeds using the Corsair-Link utility. The cooling performance is very good. I am running an i7 6700k at 4.5Ghz and the CPU consistently idles at 30c and hardly ever goes above 55c on load. Installation was also pretty straight forward. One thing that must be kept in mind is that you will need access to the back of the motherboard to install the back plate. Some cabinets will allow easy access, some will not. It is something you will need to plan for while installing.