Each project is unique. And enterprise suites have so many features, and they evolve, so it's difficult to properly compare them.
This is a play on the quote in Animal Farm by George Orwell:
All animals are equal,
but some animals are more equal than others
As of 2015-03, Adaxa Suite and WikiSuite appear to be the two alternatives with the most features. Many of the others listed here are not really ready or feature complete, but are added here because they share a similar vision of a unified platform to manage most of the information of your organization, using FLOSS.
Many of the others are personal self-hosting platforms and not suitable for teams
Adaxa Suite clearly has a suite approach, and a very large number of features (ERP, Telephony , Document Management, etc.)
Adaxa is clearly stronger than WikiSuite in ERP features. But Tiki in stronger is networking (Firewall, VPN, etc.), and Collaboration (Wiki engine).
Adaxa doesn't seem to offer a mail server, prefering to connect to an exiting mail server, as documented here
There is a Bare Metal Installation guide but no download link.
More info at: http://www.adaxa.com/
old page: https://suite.tiki.org/Tiki+Suite+alternatives