Today I posted a quick video on why an organization would want to consider replacing their Cisco Call Manager with an Asterisk solution.  The Cisco solution is nice and highly engineered.  While I am sure you would pick up some benefits in terms of flexibility with the Asterisk, the primary driver is the cost.  The fact is that once you have the Cisco solution in place, you are on a treadmill of high recurring costs.  Staff training, Smartnet, and high-priced support engineers are all part of the picture.  The Asterisk is a simple and common sense way to contain those costs.  Are you a government agency struggling with a smaller buget?  Are you a private business that could use the money to keep your people on staff rather than paying for outside support?  This may just be a solution.  It is worth the time to check it out!