The best field in Phoenix, by far, is at Chaparral High School, although the stands and other amenities could be improved.
A great total set up is at Sandra Day O'Connor.
Greenway has a total package. Also great, among others, are Sunrise Mountain, Desert Vista, and Horizon.
I have not seen Hamilton, but I cannot imagine that it, too, is not impressive. Mountain Pointe is very good, and Scotty Richardson does a great job keeping his field in shape at Tolleson.
Saguaro has a brand new field, but it could be maintained a lot better.
Gaetano Gianni has a nice field at Notre Dame.
Most of the Mesa schools should be a lot better.
I'm sure there are many others that are great, but these strike me first.