I stayed at ACT HOTEL Roppongi. The location is excellent, only about a 3-minute walk from Roppongi Station Exit 2, and close to Roppongi Hills and Tokyo Midtown.
However, the stay had many downsides. To reach the front desk you must go down stairs, which is hard with luggage. Some rooms are on a semi-basement floor, and during heavy rain I worried about flooding. The room was fine for one person but the shower was extremely small, and there was no outlet at the desk. Because the room was half underground, the window let in almost no natural light, making it feel closed.
Noise was a big issue. I could hear voices from the lobby late at night, people talking in front of the laundry, and even music played at high volume. It felt more like a foreign hostel than a Japanese hotel. Most guests and staff are foreigners, so the atmosphere is international, but those expecting quiet or Japanese-style service may be disappointed.
Another point: the only plan I saw was prepaid and non-refundable with a 100% cancellation fee. There is an elevator, but the sign is small and easy to miss.
This hotel is only good for those who care about location. If you want a quiet, comfortable stay, it is not recommended.