Disappointing hotel if location is important - states as being in Shinjuku but is most definitely not in the hub of things. The hotel offers a shuttle service from the nearest JR station but this only work from 9am to 9pm - there is NOTHING around the hotel and a taxi from the nearest station is 2000 yen -if you want to eat in the hotel then this will be expensive as well
Hotel itself is set up for the Japanese market few Westerners there, little English spoken, rooms could do with a freshen up and certainly nothing special.
Overall wouldn't recommend for sightseeing holiday due to location, and nothing special on the facilities front . Also most other hotels we stayed in Japan gave free internet this hotel charged

I stayd at the Rihga Royal Tokyo for three nights. My room was very nice, quite large and very clean. The beds were comfortable (not too soft) and the room was quiet.
Good breakfast, very nice and helpful staff. Hotel offers a free of charge shuttle bus to the next station where you can find a shopping center and many restaurants.

I loved this hotel. My room was large and gorgeous. There are many nice amenities in the room too. The bathroom is great. The only drawback was that the location of the hotel seemed a little out of the way, but it made for a very quiet stay. The staff is very cordial and eager to please.

Really beautiful, quiet hotel almost adjoining to Waseda University though the garden. Big well maintained rooms. We were upgraded to a junior suite, which boasts double vanity in the bathroom, 2 flat screen TVs, spacious seating and working areas and lovely view of the waseda university garden below.
But... if you are not familiar with Tokyo and its subway/bus system and don't at least understand Japanese, better stay some more business/touristy properties. The nearest metro station is 10 min walk and it's not easily connecting to others. The hotel provides a complimentary shuttle bus (runs every 30 min) to the nearest JR station, which takes about 10 minutes to get there and again it's only Yamanote line which is a round service, so some destinations may take over 30 minutes ride...
Don't be mislead - the hotel is not in Shinjiku, it takes 10 minutes shuttle ride to the JR stations and 2 stations by train to actual Shinjiku...