I sure noticed it in the QS4's as opposed to the QS8's.

it has a lot more than just power handling. it disperses sound far better, and the sound is cleaner. I also found it easier on the ear. The hybrid tweeter isn't as smooth.

I've also compared the M1Ti's to the M3's and M22's. The high end sound is definitely improved with the full 1 inch tweeter.