I've been to the Ossington location, as well as the one on King a handful of times. Amazing service at both locations - waiters came to check regularly, waters never empty, and no problem splitting the bill, even with large (7) parties.
My favorites at libretto are the proscuitto and arugula pizza, as well as the gnocci. Although the proscuitto and arugula were not on the menu at the King st location in Jan 2017, we were still able to order it.The marinara here is fresh, and the oil is a must-have on the pizza. The gnocci is actually fried a little bit so it forms a crisp, similar to a gnocci tater-tot (in a good way, of course).
I recommend this place to all my friends, and will never get sick of it!