Smart use of skills to proc Competent is what makes this build work, but when everything is lined up, it hits really hard. The 3pc and 5pc bonuses for Alphabridge yield a total of 15% Weapon Dmg. Savage gives another 7% against targets out of cover, and then smart procs of Competent grants another 10%. Also being able to manage Card Counter well makes the damage output really high.
But like most builds in 1.8.3, the sustainability is not great. You have to play smart. No face-tanking, etc.
As for Talents, the only flexible talent IMHO is Combat Medic. If solo, choose something else. Precision maybe, perhaps On the Move. In a group though, Combat Medic is a must.