We spent a few pleasant nights at the MyStays during our time in Osaka. Room was compact, but very comfortable and clean. Not a lot of room for suitcases and there's no closet, but there is a hanger area on the wall. There's a free wired LAN connection in the room.
The hotel has a restaurant, but we didn't try it. There are a number of restaurants in the area and quite a few convenience stores. Additionally, there is a fairly large supermarket next to the exit in the Kitahama Subway Station.
Location is in a business district and is pretty quiet, especially on the weekend, but a bit far from the shopping and dining areas of Osaka. About a 15-20 minute walk to Osaka Castle.
Overall a very pleasant stay.