Ha Long Bay in St. Petersburg does good rolling cart dim sum 7 days a week (as early as 9am on the weekends) and while it is no Yang Sing, it is very good--great atmosphere, imaginative choices and is about half the price of T. C Choy's (not knocking it, just saying it gets pricy quickly.) It's nice to have a dim sum option on the Pinellas side of the bay.
Ha Long Bay 5944 34th St. N, Suite 38-41, St. Petersburg
1. T.C. Choy's at the corner of Platt and Howard in Hyde Park;
2. Ho Ho Choy's on Fletcher (caution: there arre two Ho Ho Choy branches. The one further west does not serve dim sum);
3. China Yuan on Armenia in a U-shaped strip shopping center near the northwest corner of Armenia and Waters;
4. People tell me that Sidebern's on Howard in Hyde Park sells, or sold dim sum, but I haven't had it. Sidebern's is such a great place that I am sure the dim sum, if they still do it, would be good, too. (I also don't know what Chef Jeanie Pierola's departure has done to the menu.);
T.C. Choy's dim sum is the best. China Yuan's dim sum I've only had once, but it was good. Ho Ho Choy's is a regular haunt for me and has the best sauces. All three suffer from "mega dim sum" syndrome, which I define as the tendency to make one's dumplings too big and the wrappers too thick. None of these places is up to the standards of Singapore, where I lived for a year, or Yank Sing (or many others) in San Francisco, but they are all good and will satisfy your craving for dim sum.
T.C. Choy's probably has the most variety and is the only one using rolling steam carts. It also probably produces the highest volume of dim sum (although I have not seen what China Yuan looks like on a Sunday). This arrangement keeps the product hot and fresh. T.C. Choy's also will not bring you any sauces, or little dishes to put them in, unless you ask them, and even then, T.C. Choy's is really stingy with the amount of the sauce provided and even the number of little dishes which they will give you.
It is also the most expensive place, with the best decor and a full bar.
Ho Ho Choy and China Yuan are more traditional Chinese restaurants. Ho Ho Choy's serves beer and wine. I am uncertain about China Yuan.
If you have a taste for duck, don't order the dim sum portion at Ho Ho Choy. The meat will have been reheated in a broth and you will get a lot of bones. Instead, order a quarter or half a duck, which will give you beautiful, crisp slices of duck skin and moist breast and is well worth the extra money. (You will, probably, have to take some home.)
Almost everybody on these boards raves about China Yuan, and I have not been there enough yet to have much of an opinion. China Yuan has different things on its dim sum menu than either of the other two restaurants, items I would characterize as not typical dim sum fare. So if you are adventurous, China Yuan may be the place for you.
I have recently hear good things about places in St. Pete, but I will leave that evaluation to the St. Pete posters.