Personally, I have not noticed a difference with most of my Axioms. The exception was the M2. When I was using them as computer speakers I could not stand the highs with the grills off. These were the only set I had that I could see being described as "ear bleedingly bright", although that is a bit of hyperbole. I found that the grills tamed the highs fairly nicely.
The only other speakers that I have owned where the grills made a difference was the Paradigm Monitor 11. With those is was more of an overall grill benefit, not just a high note taming.
