Update. Having used the services finally, I can certainly vouch for this company. The staff are very accommodating when you place an order (although emailing can take time, so I was requested to call instead of using email ). The girls are very friendly (at least Yuka wss, she's certainly one of the best). She told me that she works for Hipness through her own volition (none of the girls are forced). She also refused a drink from me in the hotel, politely informing me about the devious customers who slip drugs into drinks, and then rob the girls.
I bokked an 80min course with her, and she was well worth every penny. Her English isn't great, but as I speak Japanese, it wasn't a problem. All the photos are "what you see is definitely what you get", which is a refreshing change. Yhey now have an English link on their homepage, making things easier for us foreigners.
All in all, I would recommend them to anyone. Friendly FS at a great price.