whatever you're looking for, open source has it.
As far as enterprise-ready is concerned, I don't quite agree with the classification of some products in the categories (Most mature, Maturing, Growing and Emerging). Can MySQL or Ingres honestly be called Emerging? I doubt that. As to Growing for OpenLDAP, I'd agree to a certain extent: the product is quite rock solid (which would make it "Most mature", but it needs management tools. via Connexitor Blog.