Most competitors rub, inject, and foil. The reasons are to enhance the flavor of the meat without overpowering it, limit/govern the amount of smoke on the meat, and to help keep the meat as moist and tender as possible. So, even on personal smokes, I rub, inject, and foil. The rubs I like to keep simple and not too much salt or sugar (the salt can overpower and the sugar can possibly burn). Nearly everyone who has experimented with injections ends up back close to Chris Lily's, at least the apple juice, woosy sauce, and rub in it. It helps get those flavors down in the meat. Me, I dont water down the apple juice but I dont add in extra sugar either, but that's a personal flavor preference (more fruity and a little less sugary). Foiling time really depends on your, your smoker, how much wood/smoke flavor you prefer, etc. On my extremely clean burning Lang 84 using seasoned hickory splits I'd foil at 4.5 hours. I did this (4.5 hours) yesterday using my new Bubba Grills smoker and the smoke flavor was a tad more than I prefer. So, experiment, you'll find what you prefer.
The result is well seasoned pork that is moist and tender, and the bark isn't so crunchy...
Another tip isn't so much with the cooking but with the final preparation. I know; when we pull it, it can be hot as he**. Please, pull the pork by hand, and try to keep the pieces about the size of your thumb. The thicker the piece is pulled, the better it retains moisture and frankly the better it tastes. Also, most people really hate biting in to a piece of fat. Some (particularly some here) love it, but most don't. I suggest that by pulling the pork by hand it gives you the opportunity to really make sure no fat makes it into the plate of bbq love.