My fiance and I stayed here for a week long trip and it was the perfect place. Although it's not right downtown, there's a streetcar one block away that goes straight to the center of the city (which only takes about fifteen minutes). We both loved the ride in every morning.
The apartment itself was quiet, clean, comfy, and the perfect place to come back to after long days of walking around and being on our feet. Darren & Derek also include drinks and snacks, which I thought was a great touch.
Check-in was also great! We got a tour of the apartment, keys, shown where extra towels and other amenities were, and some local tips/suggestions! If I'm ever back in Toronto I'm definitely booking again.