I've been here about 3-4 times for dim sum, and there's always something disagreable that happens. Sometimes its the service that's ultra slow, sometimes its the food that's reproachable. A visit to la Maison Kam Fung - which is in my opinion better - settled the matter for me: I don't like Le Cristal Chinois.
The venue is certainly beautiful, with the high ceilling, large windows and draped tables. It gives a great first impression, especially for events (you can rent the place for weddings, etc.). Since the dining room is enormous, you also have more chances to find a table during busy dim sum hours, when most restaurants would be packed full.
Unfortunately, the food/service fail to impress, and so I try to avoid Le Cristal if I can help it.