Nobody can match ADP's footprint in payroll processing, so it has a big leg up on rivals. As for HCM functionality and Mobile support, the players mentioned above are all among the competitors, but they skew to larger enterprises. Kenexa is a fairly high-end offering with advanced workforce analytics as its strong suit. Taleo (talent management) and Oracle Fusion HCM are the key components of Oracle's HCM cloud. SuccessFactors had a comparatively small customer count (3,500+) when acquired by SAP in 2011 but a very large seat count (15 million+). That suggests SuccessFactors is more of a competitor to ADP's Vantage HCM offering for enterprises. There are still independents out there, like Cornerstone. But where midsize businesses are concerned, it's pretty clear that ADP is the payroll and HCM leader.