I've been to all of the dim sum houses in the Phoenix area looking for one to replace my old Chicago favorite. I've yet to find anything in Arizona that even comes close to the freshness and amazing quality of what I'm used to.
That being said, during the 3 years that I've lived in Arizona, I have seen the quality of dim sum that Phoenix Palace serves increase--their shrimp dishes used to be completely inedible, as were many of their dishes containing pork. The restaurant is generally clean, but they often do not serve you water unless you personally request it, and it is definitely not filtered/clean/pure water - it tastes like it came from a rusty tap, in my opinion. We prefer their chrysanthemum tea over green, so be sure to make a special request if you want to try it. The one plus side of this location is that their business is steady so they're able to offer a large variety of dim sum.
Given the very few options we have here, this place is one of the better ones, although we prefer Mekong Palace in Mesa--and despite living close to Phoenix Palace, we usually make the longer drive to Mesa for dim sum more similar to the quality that we are used to.