I pretty much agree with all that has been written.
In fairness I have been to Coz once and so far have not really had a desire to return. My trip report raised the blood pressure of several Coz lovers but here are some of the highlights. Maybe I went with too high expectations but I was not that impressed with the topside. I never found the cheap food others talk about. I was not impressed with any place I ate and I'm not picky. Take that back, there was one small pizza joint on a back street that was great. On a couple of occasions I had rude waiters, something I have never had on Bonaire. In contrast the restaurants on Bonaire range in price widely but the food is excellent in most of them and I have never had rude service, slow yes but never rude. Another big plus for me is the water, which is safe to drink any where directly out of the tap. Fresh fruit and salads are fine to eat anywhere. I got tired of having to do with one or 2 bottles- which I had to pay for- as opposed to have a full pitcher(s) of water on the table which is the norm on Bonaire. I drink a lot when diving to keep hydrated.
Then there were the street vendors trying to get me into their store...one of which watched me eat at an outside table then tried to get me into his restaurant. I am on vacation and don't want to be hassled, you will not find street hawker on Bonaire.
The diving on Coz was great however it does not lend itself well to my preferred diving style, this is not good or bad. I dive slow, looking closely at the reef and taking photos as I go. Hanging with a group in a stiff current is difficult to do when diving this way. My typical dive on Bonaire is 35 ft for 75 to 80 minutes, the typical dive I got on Coz was 50 minutes. I do anywhere from 3 to 6 dives a day, including dawn and night dives on Bonaire for one cost, I got 2 dives per day on Coz and had to pay for more if I wanted them. I was pleased with the dive op, boats, staff and the dives but boat drift diving is just not my preferred style. I go for bottom time and there is no comparison between 2 DM lead group dive of 50 minutes and 4 or 6- 80 minute unfettered dives.
I may go back to Coz someday but I much prefer Bonaire or Roatan, they provide diving more to my liking.