A4 is king some one in the A4 post did the numbers .
https://bitcointalk.org/index.php?topic=1251930.0because of the cost for a titan and no support at all other then what we can get here . and no idea when a titan will break down and stop working that makes the a4 the best.. but im sure you know that .!!!
to compare pools for a general idea I use
http://poolpicker.eu/ but it's not the greatest my two best pools so far are
https://www.clevermining.com and
https://www.litecoinpool.org/ my third pick only because it pays in any coin you want just ask if it's not on pay out list . don't like Zpool to much no idea why i just don't .
https://prohashing.com/ but it has some issue at first loading up that can be annoying .
there are a few more that give better rewards then what pool picker lists i have found but sense I'm not in to ROI, i can't remember them and if i was i would fine them and list them for you .