The first thing you should know about this property is that it is bigger than the pictures make it seem. There is a good sized bedroom, with lots of closet space, a huge living room and a big kitchen. We stayed 3 weeks and never felt cramped.
The second thing is the location is absolutely fantastic. Just two blocks to the Q train - and the 86th street station is new, clean, and the train air conditioning works great. Not far from the Lexington Avenue line also.
Yorkville is a great place to stay. We found tons of fantastic restaurants within 3 or 4 blocks. There is a 24-hour deli with great sandwiches across the street, a newsstand across 1st avenue, a CVS, several groceries, and even a public library on York with a good used book store in the basement. (Especially if you like mysteries.) The neighborhood seems very safe.
Francesco was very responsive, answering texts almost instantly.
As for the place, the bed was plenty big and comfortable, and there is a washer and dryer a big plus for our long stay. Lots of pots and pans, and a nice stove. Good coffeemaker. No microwave, though I don't know where you'd put it. 3 good air conditioners when it was warm.
It's a walk-up, but on the second floor, so not a problem.
We'd definitely go back there. I can't think of a better place to stay.