I have to agree, that Holy Himalaya Hotel is not maybe the best in Kathmandu, but for the price you pay and service/comfort you get, this is really good choice. We have booked 3 rooms through Agoda and stayed there 7 nights. Quite long time to know all good and weak sites of the hotel. So...
Location. Hotel is situated in close to busy Thamel, but this is quiet street. This is huge advantage, because it's not that noisy and not that polluted as any other main street around. There are shops and restaurants (must try Gaia and pizzeria Tranzit nearby) in the area. Just on the corner there is Seeing Hands Clinic (check TripAdvisor info), where you could get amazing massage for very reasonable price. Hotel arranges airport pick-up for 10 USD. Our flight was delayed, but driver waited more than 2 hours for us.
Rooms are spacious, clean and comfortable. There is large air conditioner / heater, which is a bit noisy, but made its job. Could be difficult in the night, but you'll survive. Rooms were cleaned every day (unless we didn't want). Bathroom was with a shower (bathtub in other rooms). Again - nothing flashy, but most important - it was clean. Hot water is available only on certain hours, but staff will inform you about that and it didn't happen that it wasn't available. Take some of your toiletries as these provided are not for everybody’s taste. Sometimes (like in all Nepal) there are power shortages, so you have torch lamp in your room available. Wi-Fi in not working in the rooms. We had quite nice view from our windows (except field just attached, but we ignored that, lol). Small TV (I just realized that we didn't turn it on even once) and international electric plug is provided.
Reception is quite spacious and staffs was always kind and ready to help. I really liked that. The only thing I really hated and cannot understand - why there was so cold in reception and computer area. Like in the freezer. I know, that this is large space to be heated, but if you avoid keeping doors open that would warm up at some stage.
You can use rooftop terrace (we didn't have time unfortunately), but it's really nice on a sunny day or morning.
Breakfast was included in our price, but I have to say, that there is field for improvement. It could be great, but because of the cold ground floor everything was cold as well in minutes. It wasn't bad, but with small changes that could be just brilliant.
They do not have restaurant on site, but amazing Gaia restaurant is just minutes from there.
Usually in front of the hotels there are few taxis you can use for local trips. We actually had the same driver for all week and that was good deal (for us and for him). Try to negotiate rates, but from/to hotel to Boudhanath you shouldn't pay more than 450 NPR, Swayabunath 300-350 NPR etc.
On our last day hotel staff was kind enough to allow us to leave our baggage in one of the rooms until evening as our flight was quite late. Being very honest, I was glad I've chosen this hotel. Considering price I paid, location, reasonable comfort, service provided - this was really good choice. I would consider staying in Holy Himalaya Hotel next time when visiting Kathmandu.