The choice is between the R Train and the Q train? I'd take the Q every time, mostly 'cause I love the Q Train. I think the Q is one of the more attractive trains in the city in terms of commute, as it goes over the Bridge into Manhattan and you can see the downtown skyline, the Brooklyn Bridge, and the Statue of Liberty in one shot, with a sunset tossed in during the early evening. 4th ave near Prospect Ave isn't exactly scenic, but I can't think of what its like over on Ocean right now either, probably better.
On the Q you can ride out to Coney quickly too, or Brighton Beach, or Midwood.