It's because of statements like yours (not pointing at you) that I went crazy getting some to try. I don't recall seeing anyone say anything negative about it. My opinion of it now is extremely negative.
Where do you keep your rats? In the house or somewhere very, very far away? Mine are in my basement and I was having difficulty breathing a few days after cleaning. I have never seen as much waste produced. And they ate easily twice as much of the Kent vs. Mazuri so the cost savings disappeared.
I can honestly say that I have had better results, short term, with Doggy Bag dog food than with Kent. If Kent was the only food available I would give up my rats.