Great check in process for English speakers with a A4 handout given with very clear instructions and things you can use and take advantage of during your stay. Felt very safe, all guests were quiet and respectful when I stayed.
Fantastic location, close to food, arcades and shopping, and easily walkable from Shinjuku station. I'd arrived after 10 hours of flying and having never been to Japan before, found the process of locating the accommodation easy with Google Maps.
While I was concerned upon arriving to the Japan summer heat, the cooling in the capsules was adequate to me, I slept comfortably enough with the fan provided. The capsule floors themselves are air controlled also. I would have appreciated another pillow (only 1 provided) but perhaps this could be requested by staff!
Note that none of the taller capsules I observed had televisions or other technology if you wish to have that as it didn't appear super clear by the listings what they would have inside. Also, as noted by some of the other reviews, the bathing/showers are on a different floor, so are the storage lockers, so you'll need to use the elevators a bit to get around, but I never found this to be a hindrance personally.
Would recommend! Thanks for having me and making my trip to Japan a great one!