This is a very well run hostel, with some really friendly staff.
As soon as you book, you are sent a confirmation email with exact instructions in how to get there (plus the address in Chinese to give to taxi driver - very useful for westerners who can't speak the language!)
We stayed in a six bed dorm. It was average sized, clean and fairly modern. Each bed has its own reading light and plug socket. There is a heater in the room. No electric blankets, but the heater seemed to suffice (even in the dead of winter!) There are en suite bathrooms in each dorm - these are fairly small, but perfectly adequate. It can be a bit of a pain if everyone in the dorm wants to use the bathroom at the same time. The only communal bathroom is on the ground floor.
The hostel organises group activities every night (quiz, table tennis, hot pot night etc), though they didn't always seem to go ahead. I think that this may be because it was the low season and there wasn't a great deal of interest.
There are many tours available in Xian, and pretty much all of these can be booked here. They guarantee that none of the tours will dump you in a shop and hassle you to buy stuff (happens a lot in China!)
There is also a really nice roof garden. It was winter when we visited, so we didn't go up there much, but it looked like it would be pretty awesome in the summer.
A few minor gripes - they have a train station pick up service, but this is only from 12-2 in the afternoon. It's fine if your train arrives then, but if not, you're on your own (though it's not actually that far). They will also book train tickets for you, but this costs an additional 40RMB on top of the price. Whilst I understand that a booking fee is necessary, 40RMB is by far the most expensive we have encountered in China.
Wifi is available on every floor. It's very reliable, though tends to slow down at busy times.

Hantang House is located in a small alley (Nanchang Xiang) that you can easily overlook. Even after I got to the hostel and saw the alley, when I tried to find it the other day, after taking a trip around the city, I couldn't remember where it was. So I'm adding a photo of the entrance to the alley, so you can memorize it. You can also take the Shaanxi People's Government as a landmark - the Nanchang Xiang Alley is located southern to it, just a few minutes' walk.
I arranged a pick-up from the airport to the hostel (but had to ask them again and again that they will really pick me up, because their reply wasn't very clear) which cost me 150 yuan. It was a good choice to take the pick up, because my flight got delayed 4 hours and I arrived in Xi'an at 1 in the morning. I was worried that the pick-up won't wait for me that long, but I was happy to see that they waited for me.
The hostel itself looks very modern. The room is very clean, but I had a feeling that the heating wasn't that good. Music is playing in the first floor and bar all day long, which is nice. The staff were all very nice, smiled and were willing to listen and spoke English well. The food that they serve is mostly Western (and so is more expensive). I could find only around 4 types of Chinese food in the snacks menu. The tours that they offer look great and their prices aren't very high. Overall it was a nice stay.

Chinese address for taxi: 西安市新城广场南新街南长巷32号 (I would recommend you to print out important addresses before you arrive in China, because it really helps)

Excellent friendly staff and service willing to help with anything...great English..rooms and bathrooms immaculate and hot showers! Great cheap tours and Great night entertainment and overall best place to stay in china! :-)

We stayed for four nights at this upscale hostel, during our 20 days trip through China. We arrived quite early in the morning on the night train from Pingyao. We had not arranged a pick-up from the train station, but luckily we found someone holding a sign with the hostel name on it, waiting for someone else. We asked for a ride and the guy took us along, with was very nice after a long night on the train.

The Hantang House is located on a small alleyway and can be pretty hard to find. On the other hand, it is close to the subway and to the Drum and Tell Towers. You can also walk to the Muslim Quarter. So, the location is pretty good and one of the strong points of this place.

The double room we stayed in was very good. New, clean, with a good heater and a nice bathroom with lots of hot water. The room was quiet and I had a good sleep.

They had signs all over the room with the prices of items, in case of damage (towels, lamps, tv, pillows, etc). Everywhere, they were clear: "you break, you pay", "If you use the towels as a rug, you will be fined". Not very polite and welcoming, I guess. The wi-fi on the room was very weak, and most of the times we had to go to the lobby to check our e-mail or plan our trip.

The breakfast wasn't included in the room rate. You could eat in the café downstairs, but the prices were really high, and not really worth it. We walked to a bakery around the corner, where the food were good and the price, much better.

The staff were very friendly, but not really efficient. We asked for a restaurant recommendation and they gave us the direction of a noodle place, which was mentioned on Lonely Planet. We walked 20 minutes to the restaurant, but it was closed and no longer existed at that address. We also asked for a cab to be arranged to takes us to the airport (at 5 am), but when we got there, there was no taxi, even tough we had already paid. We had to rush to the streets at half past five in the morning, and get another cab (it was very cold and raining on that day). Also, we had some clothes washed and they came back with a really strong cigarette smell. Overall, we felt the staff was young and keen to help, but not very well trained and not efficient at all.

We paid 28 USD per night for a double room (through Hostel Bookers) and we felt it was good value for money. The standard price, on the other hand, was much higher, so it is advisable to book online before arrival.

Overall, it was a good place for the money we paid. The rooms was good, and the hostel seemed new and had a good vibe. The prices of the downstairs cafe was really high and the lack of wi-fi in the rooms was annoying. But the worst part was the service which, although friendly, seemed inefficient most of the time.