I usually spritz every hour, so only a couple times during the entire cook. I use a mixture of apple juice and guava nectar. I don't foil anymore, however, I've occasionally put in foil if my temp climbs a little too high, to keep them from drying out. This is more due to my inability to control temp rather than cooking technique. I then sauce them (light coat) about a half hour before I know I'm pulling them. I like the sweet stickiness created from the carmelization.
To answer your question, the spritzing doesn't really change flavor but what I'm using adds more sugar which I think carmelizes more. It may change the flavor a little but it certainly adds to the appearance in my opinion. Reading the other posts, I would agree that it doesn't change tenderness, other than keeping the skin moist.
Green OTG; Black OTS; UDS; mini-WSM; Weber Genesis Silver; USMC 86-94