I have a CAA and a CTR on two different carbines. While they are both quite different I am satisfied with both.
-The CAA that I have fits tight, (not as solid a lock up as the CTR, but as good or better than standard M4 style stocks),
-I like the recoil pad, because it gives a nice non-slip surface, and is nicer than the slip on pads I have seen for M4 stocks.
-I don't like the battery compartment so I removed it.
-I do like the adjustment lever's finger grooves.
-I don't own the cheek piece
To me the CAA is just a slightly improved M4 stock.
The CTR is a very nice stock.
-The lock-up feature is super solid.
-Again the recoil pad/extesion is non-slip.
-It is light weight.
If you get the cheek pad for the CTR it will interfere with the charging handle as well, if the stock is not fully extended.