I've been doing monthly Dim Sum events with a group of people and I am a loyal fan of this institution.
Since I've only had Dim Sum, I will only mention the Dim Sum service. The carts speed by you very quickly but slowly die off in frequency at the end of your meal.
The only reason I feel that this is the best Dim Sum in the Valley is that they take reservations unlike their competitors. I can have a group of 20 people and they will reserve no problem, well, at least when I schedule at 10:30am.
The golden gem in the Dim Sum selection is the curry tendon, melt-in-your mouth tendon that has a great curry flavor. No other Dim Sum place in Phoenix has it.