CMSWatch offers up a short article entitled "Portal Kudos and Shortcomings - Summer 2006" in which they assess 12 major enterprise products (including 3 open-source products: Plone, Liferay and JBoss) against 6 typical scenarios:

• Web Publishing
• Self-service
• Collaboration
• Enterprise Intranet
• E-business
• Enterprise Integration

CMSWatch finds Plone to be a "potential fit" for Web Publishing and Collaboration, and a "likely misfit" for an E-business portal focused on linking vendors and suppliers.  It's a pretty balanced, but ultimately somewhat shallow review that places Plone amongst some pretty elite company including Oracle, SAP, SharePoint.

Random note: Janus also thinks that Limi's accepting a job at Google is a loss for Plone.  Ummm, ok.