I have found, as expatpig stated, that if you try to hold them hot, they get a little mushy, or if you cleverly undercook them, they tend to stay a little tough. Ribs have a sweet spot in my opinion.
The standard restaurant trick, is to cook them until they hit the sweet spot, refrigerate them at that point, a flash cooler is real nice, but, who has one of those handy? Then, when ready to serve, put them over the hot grill, apply sauce and cook for 15 minutes at higher heat, to set or glaze and reheat meat. Since the ribs are already tender, if you bring to room temperature before serving, it takes just a few minutes. This allows you to serve a lot of ribs, to a lot of people, with minimal risk of not being ready to serve.
But, these are not as good as straight off the cooker. There is nothing quite like straight off the cooker, you don't need a knife, rip off a few bones and gnaw at em.