[Al_The_Man]

Camsoft is a software product, but you also need a motion control card (Galil is one) , which takes up one slot in the PC, The benefits are that the motion is controlled by the dedicated motion card and can operate in close to real time for high speed machining etc, the PC is used mainly for operator interface and also PLC functions (I/O card required) which allows sophisticated general machine control like tool changers etc.
The total cost of the high end PC based systems is getting close to the high end sytems like Fanuc or Mitsubishi, the advantage is that the open PC systems allow easier use of existing motors and drives for a retrofit.
I have been in involved in Fanuc, Mitsubishi, Camsoft, Acroloop, and some self designed retrofit systems.
Generally when looking at the cost of a retrofit or a new machine design, the cost of the retrofit system and applying it does not differ all that much between a small knee mill and a 30ft bed mill. The difference though is when the retrofit cost against a new machine is evaluated. $10,000 to $15,000 for a knee mill to $1.5m for a large bedmill. (these are replacement examples).
Al