Well, I'm a neophyte when it comes to different styles of roti - I don't notice any real differences - but I do eat a lot of it and have found both Brawta and Stir It Up on Atlantic Avenue in Brooklyn to be fine sources. I tend to prefer Stir It Up (Atlantic and 3rd) if only because they're family-run and their food tastes like Mom might make. In fact, I just had their goat roti last night.
There's also Cafe Dore on Smith Street, which has roti on their menu but which I have yet to try.
And if you're willing to go to Queens, then, hell, you should go to Jersey City. There's a little joint at Jersey Avenue and Columbus called Nicole's that serves delicious "Guayanian" roti, with their own housemade hot sauce...
For Brooklyn, try Ali's (Nostrand and Fulton, A or C trains to Nostrand Ave.) or Nio's (Church and Rogers, #2 to Church Avenue).
For the best roti, however, take the advice of Chicago Mike. Singh's is my personal favorite. (Two locations, both at the end of the A line, one at Liberty and Lefferts, the other at Liberty and 131st).