Honestly, InterCaribbean has never let me down. And they are almost always far and away the cheapest. However, their planes do suck, especially if you are tall or generally on the larger side.

The last InterCaribbean flight I was on all the fans/AC were broken and it was the hottest experience of my life. Thought I was going to stroke out.

Silver has been close to price recently, and have significantly nicer planes.

Cape Air is reliable, but has been significantly more expensive so I always end up with InterCaribbean or Silver, with Silver being my preference of late due to quality of planes.