Recently I found out that our SalesForce account is about to cap out on storage and for an additional 500MB it will cost $1500, which is crazy!  They only give you 1 Gig of storage for all users and since all emails route through SalesForce, you can imagine that it caps out quick.  I am investigation Sugar now as it has a lot of the same functionality along with being Open Source.  I’ll let you know about the cost comparison as I finish my evaluation along with any huge feature differences.