As a competitor, I would prefer to be on the Gaffers. Why? Because with all the chaos going with the Gaffers side (Duncan and Harold, LeShawna and Heather, Gwen owes the Grips) you could make it easily to the merge, if you stay quiet enough and do well in the challenges.
On the Grips side, you have Justin who controls THREE other members of your team. I wouldn't fall for his pretty boy antics so I'm pretty sure I would have been voted off first if he finds that out.