I did this comparison mainly for myself, but I tought that I could share it. I've added the links, thanks for suggestion. The three PMBs are the biggest ones at BTC-TC (and the first two are the cheapest as far as I know), if anyone want to add another - post it, I will add it to the OP. Now I have not enough time for it.

Here is two weeks old comparison from TAT with more mining assets (some are not PMB): https://bitcointalk.org/index.php?topic=223442.msg2347594#msg2347594