This is a tough one, because I really feel that The Headshrinkers were a talented, athletic, and accomplished tag team, and Owen and Davey were a great pair of technicians with terrific synergy in a short time as a team.
But I give the nod to Samu and Fatu. Look at the length of time they were together - there was nothing they didn't know about one another. They moved in tandem, were very hard to hurt, and didn't know the difference between opponents, whether large or small. They dismantled teams with power moves and speed.
I give the nod to the Shrinkers for the team longevity and experience.