Long time CQC user here. I would be more than happy to answer any questions people might have regarding the system.
IMHO, it's one of the most powerful and flexible DIY systems available today. Their pricing is built around tiers (the higher the tier the more equipment you can control), but you can intermix and change gear at any time without additional cost. So if your tier allows you to control 15 devices, you can use any 15 that CQC offers and change them at any time. This is extremely helpful because we all tend to change gear over time. If you have have a Denon receiver and then switch it out for a Integra receiver, you don't have to pay CQC additional money to use the new device. You just remove the Denon device and add the Integra device.