I enjoy Thai Tai, but not this location. I live by the one on 17th and work by this one, so I feel qualified to regale you...
The food at this location is different than the others. Its cheaper (not less expensive!). The bubble tea is sub-par, fruit choices are rarely fresh but powdered or masked by milk/sugar. The soups seem to always be half empty and the service is slow.
The reason I am giving them two stars is because they still make fast(ish) affordable food, but if you're already in Chinatown, there are way better options for soup, subs and bubble tea within a block or two.