Around 5 minutes away from Akasaka-mitsuke/Akasaka stations, which are 2 big stations connecting to various Tokyo Metro lines. That gave us huge convenience traveling to the main tourist spots in Tokyo, such as the Tokyo Tower (15 minutes), Shinjuku (15 minutes), Shibuya (10 minutes), etc. The only problem was we needed to transfer twice with luggage via train from the Narita Airport to get to the hotel, which was slightly bothersome, but if you have the budget, you can totally get to the hotel in 5 minutes by taking the Airport Limousine Bus.
The room is extremely spacious for Tokyo standards. Staff is very polite and helpful (the midnight shift can't seem to speak English well enough for basic conversations, so be aware of that if you need assistance in the middle of the night).
Overall the quality of the hotel is unmatched for such competitive price. Will totally come back should I ever visit Tokyo again.