While I realize the Achilles is not the flagship model for Xigmatek, it may very well have never been Xigmatek's intentions. It just seems a bit odd that Xigmatek opted for form over function with this cooler. With all the fan choices they have on hand, they opt to limit their coolers performance levels with the use of the 61CFM fans. I don't think that the four heat-pipe configuration is enough of a subtlety to offset the use of such a fan.
The overall performance isn't bad by any means, especially as it compares to the rest of the lineup, but by far isn't the best "bang for the buck" cooler on store shelves. With retail pricing in the $40 range, plus the addition of the Crossbow at another $10, this brings it to a $50 cooler. Even within Xigmatek's own product line-up I feel your money can be better spent.
There is one other issue I wish to address which may lend a little more to the coolers overall performance and that is the four heat-pipe design in general. The stager of the pipes in the base makes it so not the complete contact area makes contact with the HIS, diminishing its effectiveness ever so slightly. On the same train of thought, the pipes are actually too wide for the IHS as well, only utilizing half of the outer two heat-pipes. I am not the first to bring up these points about this cooler, nor I am sure I will be the last. In defense of Xigmatek, though, they have heard these complaints and have not engineered any overall design changes with the four heat-pipe coolers, so they must feel they are on a winning solution.