Boler has a voice that is pleasant to listen to, but he's not a ball knower and he's got a penchant for coming up with lame catch phrases that he runs into the ground.
Locke is much more knowledgeable about the game, and is always very prepared. I don't think he has a very radio friendly voice, its nothing to do with it being unmasculine or anything (weird direction to take it in tbh), it's just kind of grating. He's also uses weird little phrases that don't always land, but I don't feel like he overuses them as much as Boler.
At the end of the day, neither one is in the upper echelon of NBA announcers, so its just kind of arguing about what flavor of mid you prefer.