I'm a Red Sox fan, and I think their announcers are pretty much average play by play guys. Not great, but not from Chicago.
Vin Scully is pretty good, along with Joe Miller (that's the name of the ESPN Sunday night baseball one, right?) but Joe Morgan annoys me.
Blame it on bias or not, but Sterling, the Yankees announcer sounds really obnoxious. Like some Bronx teenager who is overexcited. "See ya!"
The Braves broadcasts are what most people think of baseball... boring. I don't know if it's the team itself, NL baseball, or the announcers. And don't hate on me here, I do like the Braves.
And to bring up my point about Chicago again, why did I have to learn that someone so obnoxious exists! Hawk. Kill me