Customers often ask me when they should use Microsoft Groove Server 2007 and when they should use Microsoft Groove Enterprise Services. It isn't a one size fits all conversation. You've got to consider a few variables: do you have in-house expertise with deploying web servers and other infrastructure? Do you have special security requirements such as PKI or smartcards? Do you plan on integrating with Active Directory? Al these variables figure in to the decision. My colleague Jessica provides this new paper to help you quickly move through the decision tree and get the option that is best for your Groove deployment.
Microsoft® Office Groove® 2007
Comparing Groove Enterprise Services with Onsite Groove Server 2007
http://download.microsoft.com/download/a/3/b/a3b03187-7479-4f07-9fc7-9dc454df3bbc/Office Groove 2007 Server vs Groove Enterprise Services.docx
Let me know if this makes it easier for you to find the best fit.
link to this article: http://blogs.technet.com/groove/archive/2007/11/02/groove-server-or-groove-services-is-not-one-size-fits-all.aspx