Big stock photo is a good and steady runner up.  Big Stock offers a good compensation package and their backend is organized.  Their site also accepts .jpg IPTC Meta Data and that come in handy when submitting large batches for review.  They have been a good consistent earner for me and while they do not have too many bells and whistles supporting the stock photographers community, that does not bother me because their system works.

For me Big Stock and Fotolia are neck and neck. Fotolia tries to get creative with the naming of everything and uses a credit system rather than a dollar for dollar listing.  The only downfall with Fotolia is they take a while to respond to technical issues.  When they did their big site change in 2006 I lost a load of metadata for around 1000 files that I had uploaded and it took them forever to fix the problem.  I decided after 4 months to just FTP them again to solve it instead of waiting.  Other than that I have no complaints.

123rf is a site that has undergone the most changes since it got into the game early along with iStock and Shutter Stock.   They have made the most improvements and they are always trying new things.  They just can’t seem to get the same user base and so earnings are slim with them but I support them none the less as they have a great site and they are always looking for ways to make it better.

Last and definitely least is iStock.  What can I say it is a circus in there. iStock is the first site to come up with the idea of exclusive representation in these types of sites.  Of course the idea is to be a Getty but with the power of online culture.  True, iStock has a great artists' community and the feedback and creative venues are one of a kind.  I can see why a lot of artists are cool with signing up exclusive but not for me thank you.  I would rather have an easy to use site and the community to boot.  They only let you upload a handful of images at a time and they claim this is for quality control and while that might work to a degree the network is limited.