CRM for Linux?

diwolf writes "I've looked high and low, but haven't found a real Customer Relationship Manager for Linux. I used to use ACT! for Windows (bad word, blah, blah, blah), and loved it. But, I can't find anything similar on Linux. Does this mean I have to dust off my progamming skills and write my own? Or, is there an ACT! clone that's GPL'ed and just waiting for my download?" A ZDNet article from over a year ago also makes this point stating that Linux "still falls short when it comes to supporting workloads required by applications like ERP (enterprise resource planning), business intelligence, CRM (customer relationship management) and supply chain planning". Now it's a year later, and SourceForge has racked up an impressive array of CRM related projects. For those with experience with some of these Linux CRM solutions, how well do they stack up to other well known offerings in this arena?