Very good location and nice rooms (small by most standards, but big enough by Tokyo standard). Having a washing-machine and customizable air-condition are great perks.
Only real problem I had (and reason for mediocre review) was the breakfast. You have to use the "Jonathans" restaurant on the second floor. There you get a limited menu of "breakfast sets" to choose from. Basically you get a slice of cheap white bread, an egg, a very small helping of salad and a drink bar. Even for Japanese hotels that's just very sad. Also, 1000 JPY for this sorry excuse of a meal is just a rip-off. On the second day I tried to bring some additional food from the convenience store at ground level but the staff told me to bugger off because company rules ... You can of course buy more food from Jonathans ...