- Excellent location in Ehrenfeld. So many nearby places to eat, shop, and meet others. 2 minute walk from the U-bahn stop. Felt very safe after dark and stayed lively late.- The hostess was very polite, helpful, and spoke English.- The internet speed here is quite good for a hotel/short term rental - around 70-100 mbps download.- Hosts are only present during working hours. Outside that, doors are locked and require a key card to enter the building. There's a check-in terminal outside where you can get a key on your own.But here's what you really need to know going in:- This place is hot. Hot, hot hot. There's no air conditioning here, and the sun shines right in. JOYN is only on floors 5 and up, as floors 1-4 belong to a different place which I believe is student housing. Heat rises. We measured temperatures in the room which were sometimes up to 20 degrees (F) hotter than it was outside. When we first walked into the room, it was like a wall of heat hit us and it was almost unbelievable how hot and stagnant the air was - and the curtains were closed all day.- We asked for a fan, and they gave us one, which we greatly appreciated.- The exterior shades (rolladen, as I think they are called in Germany) greatly helped reduce heat in the room. They can be controlled from the room...unless they can't be. They would often raise and lower on their own multiple times throughout the day, with no clearly discernible pattern. And usually when they would do this, they would be inoperable for several hours afterwards. It's as if they were being overridden from a central control. This made the room much, much hotter than it needed to be because when they are down the heat is dissipated outside instead of on your interior curtains.- Keeping your windows open here is essentially mandatory during your entire stay, otherwise you will surely perish from the heat. However, the windows don't stay open very well because they have a cable preventing them from fully opening. This is likely to prevent the windows from slamming open/closed from the wind, but it was annoying. The vertical opening method as is typical in European windows is possible, but doesn't afford as much airflow as you will want. Also, there's quite a bit of noise that comes from the outside, so a daytime nap is near impossible. Rooms are either facing a lively street or a park that's full of children who are having a very fun time playing and screaming as kids do.- Rooms were mostly clean, aside from some dead bugs under the windows. Bed was comfy. There was a desk to work at. The electrical plugs near the desk are extremely inconvenient to access, they require contorting your body into a very strange shape to plug in due to them being underneath the large window lip and also behind the TV mounting "wall".- Rooms had refrigerator, freezer, microwave, grill, stove top hot plate, two sinks, cutlery, and plates. One seat at the desk and a weird large and heavy chair near the door that was very inconvenient to move in case you want to sit and eat for two.- The doors don't lock from the inside. Any staff with a key card can get in whenever they want - and they did, when we were changing our clothes! Lovely little interaction there. Unfortunate, because rooms are only serviced once per week here, which is quite seldom, and it just happened to coincide with our check-in so we didn't get any service the entire stay as we stayed for just a week. It is what it is.- The elevators here are very small. Three people is a tight fit, and four is packed in like sardines. Luckily, this didn't really matter because we didn't see many other guests here during our stay.- There's shared laundry machines in the basement that cost 5 euro for a wash and dry cycle. You need to bring your own detergent. It uses the WeWash app. It was fine, you can get assigned machines with uncollected clothes in them, which is awkward.Ultimately, I wouldn't stay here again. I wouldn't recommend you stay here during summertime or fall if you are at all sensitive to heat or don't like sweating.