None of them is supposed to be "the best" since they're a crew, teamwork and all that. But experience-wise, the two "best" heisters would be:
Dallas, due to his experience as a high profile gangster and ex-hitman, thus why he leads the crew.
Chains, due to his experience as a soldier combined with his "bloodlust", thus why he's the enforcer, the guy who goes face first into the gunfights.
