For me its IS,StockXpert,SS,FT,DT weird....

Let me solve this puzzle. There are 120 ways to arrange the following sets of letters: DT, FT, IS, SS, StockXpert, so each one is used only once in the sequence. (Alpha sorted example)

There is probably someone with every one of the 120 combinations of ranking their top five sites. 

Point two: For someone else's claim that return per image is a better measure. Yes, return per image may show that IS is on top, because the uploads are limited and reviews are slow... but bottom line, sales dollars will often indicate some other site. Do you put dollars (or whatever your country uses) in your bank and spend them, or percentages? Income is a fair way to rank the sites.

I had my BME for all sites I belong to, at SS, the first month I was accepted. It's been going down since then. Oh by the way, I haven't uploaded a new image to any Micro in six months.  There are all kinds of other factors for peoples sales, like how long has the image been on the site, and how many new photos per month, that can make big changes in sales, including the return per photo.

As the portfolio grows, the return per image will drop, even if the sales increase. If they are sent to SS the immediate downloads may boost sales, but then drop fast. Some other sites, there's a steady flow of sales.

Money in the bank! That's the way to measure sites.