I stayed at Apartahotel Drake in Piantini last time, Calle Agustin Lara 29, tel 809-686-2674. 1,000 peso/night for 1 person. Clean, good security, AC, cable Tv and small fridge. This time, I'm booking into this place
about twice the price, but looks nicer with a pool on the 8th floor. They give a 15-20% discount when you book online (use the spanish reservations page) and it's located not far from Naco in the LaJulia area next to Bella Vista.
A friend of mine used to stay at Apartahotel Drake and his experience was always good. I saw his room once and it was confortable and clean. The location is also confortable. It's near wellm known streets.