Well, having seen this topic elsewhere
, I still find myself having to post again here....
I am not really on top of the newer stuff as far as blocks are concerned so I took a look at the graphs and reviews by Joe C. @ Overclockers.com to refresh my memory.
Polarflo review as opposed to the first link which goes to the overall comparisons but not a specific review.
By that I would have to say that the Polarflo looks pretty decent.
I do NOT have any personal experience with it, but I have found Joe's reviews to be on the money for every single piece of hardware he has reviewed that I DO have.