without bashing anything, i just went through getting another heat sync for one computer, i had 3 things, err 4 thing, i mean 10 things i ended up as conciderations.
(3 when i went out to buy, 10 when i realised what they were selling still)
Nice copper base
either copper inset heat pipes or touch style, prefer flat copper base to bad touch style with gaps between disimaler metals
the base should not be a waste, if it is going to be there and a big gap too, Fin it
120mm fan + possibility for adding one more if ever needed
Non-propriatary fan, because fans die, and then i have to completly remod one to fit thier spaces
actual duel ball bearing fan, last 3 times longer , and make less noise Later in time.
Fan can be purchaced seperate i dont care what they put on the thing.
4 pin PWM capable
mount for the board type, mount can be irritating as long as it isnt useless
Clearance for rams
clearance for chipset , be that high towering or just the right size, in this board it was 120x120+
i do not like too long distances between base and cooling fins , being horizontal heat pipes are not AS fast
general Heat pipe logic , lots of square inches of heat transfer be that many pipes or less big fat suckers
Within 3-4 degrees of the better coolers when tested
not excessive in weight, because it is going horizontal.
I didnt need Cute , led, or really want a lot of Art , especially if it effects something.
i got 7 of 10 for the one i got. but that was all they had local :-(
------------------
the square fails on fan propriety , fan size , re-configuring ability.
has nice base , adequite heat piping , unnessisary cap on top, removable.
there is also 2-3 versions of it too, dont know which one you were talking about.
http://www.frostytech.com/articleview.cfm?articleid=2213&page=4
testing temps are ok, but not great , sound is relative to 92mm fans.
another thing to concider with a Fan in the center model, even things like spinQ or zalman,
you cant take the fan off and have working room for assembly. could be a big assembly concideration
-----------------------------------
i ended up with an Open side style instead of boxed up with plastic. i did not like the boxed up style.
At home analized fan flow
the fan was balanced better having a deeper pitch at the hub, and less pitch at the end of the fans blades
still lots of the air shoots out the side of the cooler , covering with hands the sides, certannly Jamms more air through the cooler
but i could add in something easy if i thought that was nessisary.
stupid machined base was terrible, took 15 min to resurface it a bit.
another thing that some makers think is cute to do is have a convex base for the processor, i dont agree with that, when seeing the 2 core items (quad) in there i am trying to cool, and i now have a lapped processor, flat is fine. even though convex might work on a test base better.
.