I just read a study looking at the ATS marketplace, the relative market share, and growth rate. In short, Taleo, with an eroding leadership, is still #1. There are more ATS suppliers than ever -- the study below monitored a grand total of 109!

Should you change your ATS?

If you are a SMB, GoogleHire seems to be a good offering if you use the Gsuite of products, GreenHouse has a well-oiled sales machine, and SmartRecruiters' response to Google's entry into the world of ATS, by offering its system free is hard to beat.

(In other words, what you would have expected free from google is used against them.)
If you are an enterprise with a global footprint, it seems that Workday leads their share of new customers, with iCIMs and SuccessFactors following respectively. However, it remains to be seem if Workday will put enough emphasis on their ATS platform to retain customers.

But what I see as the most important factor to consider while revisiting your ATS platform is: Do they integrate well with the best of breed?
The market has shown over and over again that, while big integrated platforms have their appeal, their lack of best-in-class innovation makes organizations end up with integrated software.

Read the full study.