A Badly Tarnished Jewel
My wife and I recently stayed 4 nights at the Arizona Biltmore. Let me start out by staying they do a lot of things right -- we got an incredible all-inclusive deal that came with a waiver of the resort fees, self-parking fees, discounts off spa treatments and very generous meal vouchers (we spent less than $100 for five meals in total and most of that was for a bottle of wine with one dinner). The staff is unfailingly polite and helpful. The pool is great and the landscaping impeccable.
So why the 2-star review? The place is, sadly, falling apart.
Students of modern architecture (and I am one) and fans of Frank Lloyd Wright (a consultant on this project, though not the architect of record) know the history and the signficance of this hotel. And the hotel never lets you forget its pedigree, nor that it has hosted all Presidents since Hoover and many, many Hollywood celebrities. So, that's why it's a heartbreaking tragedy to see the hotel in the condition its in.
The owners and General Manager need to be held accountable for the deplorable condition of the structure. As you see from the photos, there has been a criminal neglect of basic maintenance for many, many years. None of these problems developed overnight. The crumbling wall you see was outside our patio. The chipped paint was on the convention/ballroom side which gets lots of traffic. 
As if that weren't bad enough, basic housekeeping is lacking. The base of our room toilet was badly rusted. The paint under the eaves of the spa (visible from the central lounge) is chipping badly and screens have been knocked out of place. In the men's locker room one shower had a door that would not close, and another shower stall displayed mold and mildew. The furnishings in most of the public areas look tired and faded.
I hear a new GM has been appointed. I hope he/she recognizes the need for a serious plan to repair badly worn areas and bring the hotel back to its former glory. It won't be easy, fast, or cheap. But the poor decisions in the past have made it necessary.
Bottom line -- if you can get a cheap rate and lots of added value, probably OK. But, north of $200/night, I'd go elsewhere. Phoenix has too many world class resorts to accept this one-time jewel.