As a native Chinese, I'm an avid fan of dim sum and have eaten at quite a few restaurants, but I don't have anything good to say about Great Eastern. The food was only average (the shrimp dumplings fell apart when we picked them up, everything was lukewarm, and there was layer over our porridge after it'd been sitting out too long), the decorations shabby, and the service was HORRIBLE. The waiters were downright curt with us, dumping our food on the table with a scowl before they whisked off somewhere else. No joke - I think I've been treated that way only once or twice in my life.
I think it had to do with the fact that we had dressed casually and weren't foreigners, sadly enough. Many popular Chinese restaurants I've tried have always looked down on the "native" eaters, with the assumption that we're not the worthy customers. Paranoia? No, this behavior's common in China too, and I'm only sorry that the servers had such big egos here.
My suggestion is to try a smaller, less-hyped restaurant. The food here is only mediocre, and it can be had for a lot cheaper at a family restaurant. (Yes, they look cramped and shabby, but the owners love their customers!) My $7.50 quail egg porridge is usually only $4 anywhere else I go - the prices are so inflated because they know they can get away with it.
Ugh. I'm sure many people have had great experiences, but I would never go back to that restaurant. This place is popular for food that I could get anywhere else for better service, less wait time, and probably a cleaner restroom as well (although in SF, that's hard to find).
Pros: Popular, great tourist trap
Cons: Bad service, food's so-so, bathroom's under the stairwell, shabby ambience, long wait time