Beautiful property is a less than ideal location; some improvement needed; nickel & diming attitude lets it down
I would like to score this property higher but I could only say it is "very good" by overlooking some definite drawbacks. Overall the hotel is beautiful: the buildings are beautifully done and the public spaces look excellent; the landscaping is superb; everything is as one would hope for an upscale resort hotel. But, as I mention below, the hotel lets itself down in ways that are quite unnecessary and could be easily cured if management wants to do so.
The bedroom was spacious and comfortable. The bathroom was spacious and reasonably well laid out. It is not ideal that the toilet is right by the shower (2' distance). I was staying by myself so it wasn't a problem for me, but if two people were sharing the bathroom it would not be optimal. 
What is a problem in my opinion is that the housekeeping (or maybe maintenance) is obviously more superficial than it should be. I looked across from the shower and noticed that the air-conditioning vent had thick, nasty accumulation of dust, dirt and who knows what else - see the photo. In a hotel with 900+ rooms there should be a proper maintenance schedule to take care of vent cleaning on a regular basis - apparently the Marriott Desert Ridge lacks such a maintenance problem. And that raises another question: if their approach to maintenance is poor, what else in the room/bathroom/hotel is not kept properly clean?
Whether the location of the resort works for someone depends totally on what they are there to do and whether they want to be going into metro Phoenix. The resort is a major freeway drive away from most of central Phoenix - plan on 20-30 minutes to get places, more if you hit traffic jams. If you just plan to stay at the resort the whole time that won't matter to you.
Nickel & diming: the resort imposes a daily resort fee of $25+tax ($28.32/day), which I did not know about before I arrived. What do you get in return for the resort fee? Nothing. Not WiFi, not valet parking, not even a newspaper - nothing, nada, zip. So what is the resort fee really? It is a hidden, second-stage room cost that is not shown as the room cost - so the hotel rate seems to be one price when actually it is the displayed price + another $25. At least some resorts include free WiFi, phone calls, newspapers, and valet parking in return for the daily fee. 
Other gripes: 
(1) the towels in the room are poor quality, tired, worn out. If my room/bathroom was a guide, then the resort needs to get new towels that are resort quality. If this was a 4 star property I would not make this point (though I have stayed in 4 star places with better towels) - but this is a 5 star JW Marriott resort and should be judged by that standard.
(2) Lunchtime dining options could be improved: I was told of just two options - The Meritage and Blue Sage. I expect there is poolside dining but I was not by the pool so I don't know. I opted for Meritage, which is the hotel's steakhouse and should have been their best restaurant. The service was VERY slow and the food was indifferent. A pleasant but unexceptional crabcake, calamari that must have been cooked from a frozen packet (and would have been unacceptable at Applebee's), entrees that were unexciting. Overpriced wine by the glass.
(3) Intrusive sales pitch by Marriott Vacation Club. Phone message, papers under the door, urging the guest to stop by the desk and let them make their sales pitch. I have a couple of Marriott Vacation Club memberships so I am friendly to the general concept, but I don't want it pushed at me in a hotel when I am not indicating that I want to know about the product.
Every one of the negatives I have mentioned could be solved easily and quickly by a hotel management that cares. Remove the negatives and I would rate the resort as very good.
Final note: when I objected to the resort charge because I had not been told about it in advance the lady at the front desk removed the charges, and when I showed her the photo of the air-conditioning vent she seemed genuinely upset and concerned and said she would report it. So, the front desk attitude on check out was appropriate. But it should not have been necessary in the first place.