Haidilao is well-known for excellent service. At the Sanlitun location I experienced a sort of valet-bike parking, where someone helped me find a bay for my bike, and asked if I needed help carrying my bags inside, and when Wendy and I specified that we were strict vegetarians they went out of their way to double check what that meant stockwise, and what would be okay and not okay. It is more expensive than some of the other hotpot restaurants I've been to here in Beijing, though. And it's much, much harder to get a table. At the Wangfujing branch we booked ahead, and the waiting area was full when we went to depart; at Sanlitun we ended up waiting for about 40 minutes to get a table. They provide you with snacks, games to play, and a free manicure while you're waiting for a table, and LN says she often doesn't book if she needs a manicure, so she can wait and get one.
The mushroom broth was amazing, filled with mushrooms and some garlic it had such an excellent flavour. The spicy broth was also quite excellent.
The thing I love about Haidilao is its excessive complementary condiment wall. Mixing sauces is an excellent part of the hotpot experience - you can choose from (among others) soy sauce ("home made"), sesame sauce, sesame oil, fried peanuts, a soybean paste, a mushroom sauce, a variety of chillis dried, fresh and oiled, green things, vinegar, other types of nuts, and even msg, and that's all without touching the condiments I can't eat. LN introduced me to the concept of creating a dry rub for myself, she used a mixture of salt, dried chillis, and peanuts, which I thought was pretty excellent (though very spicy). The condiments bar also includes a variety of fruits, a pumpkin soup, and some cold Beijing salads (such as tudousi and the smoked tofu strings thing).
At Wangfujing ordering takes place via ipad, all in Chinese but with pictures. Ordering at Sanlitun is via a sheet of paper all in characters, but some places (such as Little Sheep) have menus with pictures if you ask for it, so that might still be available.
Haidilao also has noodle dancers, lovely clean toilets, and an awesome array of tofu to put in the boat.
Various locations around Beijing
Some locations (such as Wangfujing) have lifts, but others are old and not at all accessible.
Website allegedly has an English version but I've never been able to access it.