We booked Citadines in Tokyo based on the great reviews in Tripadvisor and our experience in Citadines Kyoto. The Tokyo Citadines offers a nice amount of space for the money you pay (especially when you consider that this is Tokyo!) and the room is ok and has all the stuff you normally expect in Citadines, but that's it for the good sides.
The sound insulation is poor at best. For example the front door lets in all of the sounds from the corridor, so if someone passes your room or talks in front of it, it almost feels like they're in the bed next to you - fortunately there wasn't that much corridor traffic or night crawlers in Citadines at the time we visited. Also from the bedroom window sounds get in very strongly. At the time of our visit there was a construction work right next to our bedroom window and they were working every day starting from 08am in the morning. Although the sounds weren't super loud, you would always wake up to this - fortunately they finished always after 4-5pm and at night time there weren't much sounds from outside. It might be that if your room is on the other side of the building that you wont get the construction noise. But then again I've heard that some of the other rooms that face the bigger road on the other side of the building get lots of road noise 24/7, so it's a lose-lose situation from this point of view.
As I mentioned there's no construction noise at night fortunately, and in any case it wasn't as loud as we feared when we first read about the construction on the notification in our room. In any case I really dont understand why hotels dont mention in their web booking service or elsewhere if there's a big construction going on nearby, this is a huge factor for deciding whether to stay or not, and I always feel cheated when this happens (had this 3 times in different hjotels) and feels that you're paying for more than what it's worth. It always gets negative WOM when this happens.
Other than the noise, I have to say that the overall atmosphere and ambience in the room was adequate at best compared to Citadines Kyoto. I don't know if it was the lightning or the air in the room or the furniture (or the fact that the room was a bit smaller and the layout was different), but somehow it missed the same comfortable and relaxing homelike feeling that we got in Kyoto Citadines.
The location isn't that good either. The property advertises itself as having a prime location, but still it is quite a walk from the closest subway stop - and far from the central Shinjuku. I can't say that the location would be bad, but it isn't that great either.
Can't say much about the service, because we didn't really have special needs, but when we checked in the procedure was a bit slower and sloppier than usual because of the trainee that handled our check-in, but this is no problem of course. However the room was always cleaned in time and to great detail, but this is more of a rule rather than an exception in Japan in my experience.
Overall what can be said is that the Citadines Shinjuku is not up to scratch if compared with the Citadines in Kyoto, but for the money paid it still offers very good value in Tokyo. If you need a bit bigger apartment type room in Tokyo with quite a low price and for a time that's not long enough to rent a premium apartment from lets say the roppongi area, then Citadines Tokyo might be a great choice. However considering the noise factor and the fact that the location is a bit off, next time I'll probably invest my money somewhere else.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.