I just did a root beer marinade and it came out pretty good. I also injected with a root beer pineapple and rub solution, meat came out kinda dark, looked like it was sauced. If your completely new to this do your research, theres plenty of info all over this site and the web. Youtube is nice too cause you can get some visual aid. Im still a newbie but the number one thing ive learned with butts is plan for it to take a lot longer than expected. My root beer one this weekend sat in the smoker for 18 hours and only got to 193. Time before that I foiled at 160 and finished in the oven because of weather and still took 14 hrs to get 195. And these are all butts under 8 pounds!
Good Luck and make sure to post some Q-View!!