Crystal Jade is our favourite restaurant for xiao long bao in the Central/Admiralty area. It's a top value for quality food.
Service is quick and efficient. Just be prepared to wait for a table; they don't take reservations. The wait at lunchtime can be especially long: 1/2 hour or more. At IFC mall, queue up for lunch before 11:50. For dinner, we usually go to the Queensway branch, where the wait is shorter.
As for the food, we love the xiao long bao and consistently order several baskets of them. We also like the tan tan mian, although I wish it were spicier, and the green beans with minced pork.
The restaurant is casual, busy, and noisy. Not a place for a romantic dinner, but it's clean and not shabby looking. To me, the busy atmosphere adds to the excitement of eating there and there's no requirement to change.
To sum up, what we like best is the xiao long bao and what we like least is the wait.