Stayed for 3 days in one of the apartments with two others. Has decent amenities (kitchen, TV, Wi-Fi), though Wi-Fi needed a reboot at first. Fairly spacious and had a pullout bed and one larger double bed. Pretty bare-bones extended stay scenario for most folks there, and the anonymity afforded by the fact that it does not look like a hotel at all from the front makes it pretty good for some folks. It's also very close to a lot of the UN buildings.
There was a rather annoying heating duct clang occasionally in the evening.
The cleaning crew came early the day I was to check out, so I felt a bit rushed to leave.
I did leave my phone charger there and I had the hardest time getting to the customer service folks, which I think is a pretty major drawback. I was rerouted across multiple folks on the phone, and eventually gave up on getting it back. If you're choosing Elite City Stays, just make sure you can handle things on your own, because there's no-one on-site to help you.