Casinos?
I am not a judge of casinos, However the board may need some additional help from you because your question requires some more input to have a informed response from my fellow posters.
Are you visiting the country just to go to the "best"casino?
Where are you going, have you already made plans to stay in a certain area, such as Santo Domingo, South, North, Central, or East?
If you have made plans to stay in a certain area, then one of the posters will be able to direct you to the "best" casino in the area, unless you like to travel long distances.
If you like to travel and/or have not yet selected an area to set up camp, you may be advised of the "best" casino in the country. Regards, PJT