So far, we have used Insel once and Delta several times in recent years. We are going to Bonaire next Saturday on Delta for about our 25th trip since 1986.
We used Insel about 3 years ago when they were doing nonstop to BON from Miami and that worked well. I monitored their "lateness" for a couple of months back then and it averaged 25 minutes late leaving MIA. But they had some waay late flights too-2 to 6 hours. Coming back via CUR on Insel, it was a very easy connection to Insel's MIA flight versus others as we only had to wait at the gate......It appears that cancelled flights are the main problem. I would tend to go back to CUR the day before a flight to the US to ensure being there for the flight. Delta works well for us as we get more than half a day of extra diving as their schedule is great both ways. Arrives before 2 pm--leaves at 2:30pm, so we can dive well into Friday afternoon. We do feel we need to be in Atlanta the previous day to catch Delta to BON at 945am on Saturday. We are doing MIA-ATL next Friday and onward to BON next Saturday!
The next best Miami--Bonaire connection for us is AA to Curacao and DiviDivi Air to Bonaire. DiviDivi is the only reliable airline flying locally. Last flight, last time I looked; is 5pm. Weekends have a reduced schedule so check thoroughly. Book by email or online directly with DiviDivi Air.