Chael is definitely one of the more complicated and interesting fighters in UFC history. On the one hand, he was a fantastic showman that did bring in the era of self-promotion. I have very mixed feelings on that because while it gave some fighters an avenue to make even more money and gain more exposure, it has also lead to a delegitimizing of the sport aspect, which I think causes much more long-term harm to the UFC and MMA.
On the other hand, he was a true contender at 185lbs, and he has a few impressive wins at 205lbs. His history of PEDs is pretty bad, but unlike some fighters [cough, Josh Barnett, cough] he never made excuses for it, and he owns it every time.
Ultimately, I think Chael makes the sport as a whole better because he injects a very unique element, and I think a lot of his commentary is truly insightful. I like to hear what he has to say on some subjects, but I turn off when he starts to shill too much for Dana White and Conor McGregor. However, I'll always appreciate this classic line:
" You tell Anderson Silva that I'm coming over and I'm kicking down his backdoor and patting his little lady on the ass and I'm telling her to make me a steak, medium-rare just how I like it.”