NZXT really did their homework here. I have seen quite a few of the AIO solutions that have hit the market, and not since Antec jumped into the market was there a solution as full featured as this unit is out of the box. Not only do you get the obviously larger cooler with the Kraken series of coolers, where you do get 36% more area to cool the coolant inside of the loop. Even with three wires coming out of the head unit, the fact that they are sleeved with braided nylon really keeps the wiring super clean when installed in a chassis. One other thing I really liked that I remember was a slight issue with the Antec version, the USB cable on the NZXT Kraken is more than long enough to use on any current motherboard and have no issues reaching the USB ports. Speaking of additional length, for those that don't want to install this in the back of the chassis, the 15 inches of tubing between the head unit and the radiator open the possibilities of locations inside of huge cases to mount this. The last thing that really bumps this product up another peg is that without an extra purchase, you can fully control every aspect any user could ask for via the software.
The performance of the NZXT Kraken X40 is really good, sliding right in with the Corsair H110, which is a solution that offers a dual 140mm radiator, so that is really saying something for the Kraken series. There is a downfall to this performance increase though, and that is the fans. While it only takes one look at the audio results, specifically the overclocked run where the fans were allowed to assume their maximum potential, they were loud. To be able to hear this fan through the headset while gaming is one thing, but without them on, there was a steady drone of a hum coming from across the room that drowns out three other PCs in the same room. On the flip side, you aren't always going to want to run the Extreme profile, but if you are benching or gaming with a heavy overclock, I would get those fans pumping at this speed sooner than later, or expect the thermal results to climb. I do like that there is software to make finite settings to the system, because with just motherboard control, you get wither PWM control if the board offers that, or you can max everything out. With the handy and easy to use software, it almost trumps the loudness of the X40.
Considering that the H90 is the head to head competition for the Kraken X40, NZXT is priced exactly the same on Newegg. So not only do you get slightly more performance at the expense of sound levels, you also get the software to gain complete control of the X40, but the fully customizable choice of colors on the head unit, it may be what AIO buyers are looking for, but missing from most other offerings out there. All things considered, I am willing to overlook a bit of noise to gain this amount of a performance increase, and since we are talking apples to apples with the H90 and the X40, there is no conceivable reason to buy the H90 with this being offered. Why on earth would you give up on the LED lighting and software, just for the name over the CPU?
In reality, this is the cooler to beat right now, and since NZXT was first in the world with a 140mm solution, I wish I had these before the Corsair units, as I may have been a little harsher with those designs than I was at that time. Seeing what NZXT brought with the Kraken X40 AIO, there really is not a better single 140mm radiator cooled solution being offered right now.