Personally, I think you're better off taking the specialist unless you're talking about a huge impact player.
Depends. If your players in the years they are selected are extremely well rounded players and great in many facets of the game, do you really need a specialist.
For instance. Portland has Sam Jones, Tiny Archibald and Larry Bird in the backcourt and wing. If you need a clutch three pointer are you really going to take out one of them to put in some three point shooting specialist because there's no 3 point stats on Sam Jones and very little on Tiny?
Tiny, Sam and Larry are three of the most clutch outside shooters the game ever saw. Does this team really need a three point specialist are would they be better off with a BPA in case one of the players in front of him gets hurt.
OTOH, not every team is going to have players that have 5 tools, so to say stealing a baseball term, so I can see the need for specialists. Ultimately, it will come down to preference both in putting a team together and judging.