Owners and font office types will tell you no.
Players, especially his clients, tend to disagree.
I think owners tend to roll their eyes at him because he has a megaphone that is sometimes used to distort what they feel is the truth.
But players should appreciate his presence, because he's often setting the pro-player talking points every offseason, and he's front and center of this current debate: players who say owners are being cheap vs. owners who say players and their agents are making unrealistic demands.
I would advise any non-superstar players to find a different agent, because I don't think Boras' approach of waiting, waiting and waiting until a team gets desperate is going to fare well for non-superstar players in this current age.
If you are not Bryce Harper or Manny Machado (and maybe if you are) you are better off accepting a healthy extension before free agency, or taking what seems to be a strong deal as soon as it pops up.
A lot of guys have already overplayed their hands and been forced to settle for less as a result. Example: Yasmani Grandal. I don't care what he says about what he makes for one season, if he truly passed up on that multi-year offer from the Mets, he played himself.