In my experience with enterprise SASS products they mostly use SAML and most companies I work for use it. At the time I was trying to switch to OAuth or OpenID

In my experience with enterprise SASS products they mostly use SAML and most companies I work for use it. At the time I was trying to switch to OAuth or OpenID but the support was severely lacking for off the shelf enterprise software, especially older stuff. ForgeRock was also giving the identity management team issues so SAML was the only option.