I have the GCM 12 SDE not sure what the differences are. Mine works well for me and while there are a couple of niggles I am sure I would have similar niggles with any other CMS as well.
Nothing major: The only one I can think of is the motor catches on the hold down when tilted to the right, of course I will only be chopping little off with the wood already clamped on the right and it is more convenient to tilt to the right. Would not expect any other saw to be different.
Apart from that I am not sure there is anything that is not just an issue with me
The dust collection is reasonable if I remember to reattach the hose. It is accurate and repeatable. When I check the angle with one of these magnetic thingys it gives the same angle within the tolerance of the thingy when the angle is changed and moved back to a stop.