My thought on why they aren't used more is pretty simple. Either everyone on here read the "great 12 challenge" done about 2 years ago, and took the results as fact, that it isn't a good driver, which if anyone ever gets the chance to listen to one you'll realize how off base that is. Or two, someone DID try one, ran 1k watts to it (thermal limits of the driver) and popped it in like 20 minutes, came back here crying about it and it got a bad name.
It wasn't mean to be a high output driver, but it easily plays loud enough for what I need, it was however, designed to be a small box, low distortion driver. In my opinion it does both of those extremely well.