I have a RibOLater and we actually used it in competition for a full season to cook ribs in a 22" WSM with the Cajun Bandit rotisserie ring. We earned a handful of 1st Place rib calls in the process too.
While I agree with what has been said already about it being a gadget and somewhat cumbersome to clean, it also cooked the ribs very evenly. We didn't have any issues with the meat falling out as St. Louis cut spares filled the trays and were quite balanced. However, I can see how there could be issues with smaller items like chicken pieces, shrimp, fish fillets, etc. They would require more attention to make sure they are balanced.
We had fun with it!