In terms of configuring the IPS, what's the difference in the experience using the CSM vs. the IME? I have a PC running IME here at office but I'm having issues installing the CSM so I haven't been able to try it out. I am, however, looking at CSM for centralised security management.
Is the interface on the IME much better than the CSM? If so, is it that much better that you'd say that the cost of the extra device (IME) of having both outweighs the benefits?
Both CSM and IME can do signature tuning. CSM lets you create a shared policy with your signature settings to deploy to multiple sensors. That way if you need to tune a signature, you can make the changes on a policy level and have that cascaded down to all your sensors without having to touch the signature policies on each sensor.