The Black Ice is a four-pass copper-core radiator which is very easy to mount without any case mods, fits one 120mm fan perfectly.
The Hayden 1676 is an aluminum stacked-plate cooler, which can be used with two 120mm fans, (albeit a tad narrow for 120's, might fit three 92's better.)
I just switched from a Hayden 1676 to a Black Ice, (all other things remaining equal), and my temps dropped by about 2C.
I originally decided to go with the Black Ice instead of the Hayden to avoid the galvanic corrosion issue, and to avoid needing case modifications, (with my case, I would have had to mount the Hayden outside the case with plumbing through the back-panel, I didn't really have the tools to do that.)
Dunno which of the two has the most heat capacity, but I am satisfied with the easier to mount Black Ice, which seems to be performing better in my system than the Hayden.
