A few things here....
The AES is essentially a box that combines the following items (for $3750)....if you include an audio card (or two or three) the price will go up more.
2. CEN-TRACK (Empty)
That being said, the AES is in the process of being phased out and out of that list of 4 Crestron products, one is already gone, two have been replaced by newer models (SWAMP8x24 and MC3) which only leaves the CEN-TRACK as current.
Therefore, what specifically do you need? Have you been quoted the model with the extra cards? How many rooms do you have? In order to do a full analysis, you need to provide some additional details.