In a kind of desperate gambit I've been twice to Neo-China in Cary, once for dim sum and once for dinner. Neo-China in Durham is indeed owned by the same folks, though dim sum is served only in Cary.
The dim sum was acceptable but not spectacular; roughly on par in terms of both quality and variety with the dim sum at Hong Kong Restaurant. The food at Hong Kong may be a little funkier and spicier and more authentic, but it's also a bit heavier, with a tendency to arrive cold. The primary difference is decor: Neo-China is sleek and modern (maybe overly sleek and annoyingly modern, rather like an expensive dentist's waiting room), while Hong Kong is an unapologetic dump. In the final analysis I would opt for Neo-China by a hair.
Dinner at Neo-China was indistiguishable from dinner at Neo-China in Durham. Westernized and sweet. I wouldn't bother.
Service at Neo-China is excellent: friendly, prompt, etc.