I've stayed here numerous times over the last ten years and it is definitely the best low-cost hotel in Tokyo. I'll be staying again in a week and am looking forward to it. The rooms are clean, the staff friendly and always ready to rectify any mistakes (this is Japan after all). The central location is excellent. Rooms are small (this is Japan after all) but no worse than places I have stayed at in London at twice the price and half the service. Amenities are excellent.
In-house breakfast sets you up for the day or there is a Starbucks up the road.
My only advice would be to go for a semi-double room (if you're by yourself) in the newer part of the hotel and book early.

the hotel is just 3 mins walk from aoyama itchome subway station, 10 mins walk from the infamous roppongi street, the rooms are small, there is a wired internet in the rooms with good connectivity, toilets feel claustrophobic but hey this is tokyo and for this city, this room is good for the price they charge, unlimited bottled water, toiletries, coin laundry, quiet neighborhood and plenty of restaurants and convinience stores close by, cigarette stench is all around, but it is in other hotels i have stayed as well, bring a travel electrical adapter as your normal plugs dont work, motown bar is a good one close by.
cant complain for the price i got

The only affordable option we could find in Tokyo. Single room small but ok for a short stay. Great location short walk from underground station. Downside was overwhelming smell of stale cigarettes in the room despite it being a non-smoking room.

This is the perfect hotel to fit your budget. We went in April when the highest season for Cherry Blossom in Japan, and the rate was still so good! So we can save money for the marvellous Japanese food. The room wasn't so small as we expected. You can expect the room to be clean and tidy when you get back to the hotel at the end of the day. Staff can speak unbelievably good English. And they are very helpful. Location is also good. Only 5 minutes walk to Aoyama-Itchome station and only around 2 or 3 minutes longer to walk to Roppongi.

Highly recommend!!!