Mona's by far is my favorite spot for roti. Personal favorite is the jerk chicken roti. You can see them churning out the roti at the back. Taste so fresh! There's always a line-up.
I've also tried Roti Hut (also read great reviews online), but it's just not as good as Mona's. Their roti seems to be thicker and meats are less flavorful in comparison. It's still great roti, but just not as good as Mona's.