There are mixed reviews on here and I can appreciate why. Depending on the day and time you go, it can be calm and relaxing with great selection or mobbed and a poor selection. Also, you may get alot of help or no help at all. Just be aware that it's a popular place during the weekend sales and the interesting pieces may all be sold out. Then a few days later all kinds of great pieces will be out on the tables. Very hit or miss.
If you are prepared and know what you want it can be good, but don't take things personally. Some people have rough personalities and your serenity may get dented. But this is Phoenix! the big city. That said, there are some interesting exotic pieces and good quality semi-precious stones.