The reason I said so is that there's a new spa in town named Ayatana Spa and it has defined the word "luxury" accordingly.
I went for a business meeting at Shambala Hotel in Maharajgunj and landed at Ayatana Spa, as its owner approached in a friendly way (nearby), cause he was nicely explaining about the hotel facilities (including Roof Top Swimming with an outstanding 360 deg view of Kathmandu, excellent). So I insisted to take a look.
The hotel is newly built and so as the spa. The moment we entered in the spa, it gave me very warm and earthy impression. We took a tour in the two storeys spa and I made an instant reservation for two, cause they were having promotions.
After two days, we went for Steam Bath and Re-Energizing package. Staffs were really warm and professional in terms of customer service. We were on time, and everything was prepared, we didn't have to wait for even five minutes. The thing I liked about their front staff is that they were able to differentiate and explain types of massage treatments which has different benefits according to the stress level, one has (knowledgeable enough, well trained). Got insights from the conversation, and thanked her after 2.5hrs of time there.
Ayatana Spa is recommended. Not only for luxury but peace of mind as well. Their price is also very moderate in comparison to other days spa's in the Hotels.