I wore them for years but I must admit that I really see no point to the single breasted dinner jacket any longer. A double breasted means one can dispense with vest or cummerbund, and be slightly more comfortable so without looking like a man who never learned how to dress. And, being rarer than its single breasted relation, the DB also stands out in an unobtrusive way should such a thing be possible.
The only time that it might make sense to put a single breasted in one's closet is if a man needs two of them because he is called upon to wear dinner clothes on consecutive nights with some frequency (there may be a thousand such men remaining on the planet). But even under those circumstances a second double breasted makes more sense to me. It can be adequately differentiated from the first by color, cloth and collar style after all. But even that amount of difference is hardly necessary and probably less important than possession of a bow tie with a different shape than the first and a second dress set for a change of pace. If you plan to shop for a dinner jacket this season, look for a double breasted.