One weakness of the CX 15 is that if you have it locked down on a cut pile carpet the first time that you trigger it, it tends to put circles in the carpet at the first placement that may be troublesome to remove.
To avoid that, you need to depress the trigger with the tool tilted slightly upward and then slowly put it down onto the carpet while already pulling it away.
That level of difficulty, and the resulting bathing of baseboards, relegated that tool to the dumpster of cleaning tool history in my book.
On level loop it doesn't have that challenge.