When I look at the Phoenix luxury market, I see it in 2 categories: North Phoenix (newer homes) with areas such as Desert Ridge, Tramonto, 85254, etc. To the south, you have the older, historical neighborhoods like Willow, F.Q. Story, Encanto etc.
I did a search and looked at everything north of Dunlap (N Phx) and to the south for the month of September. N Phoenix is faring much better, with days on market (DOM) @ 166. Homes are selling in the $260's/sf at about 15% less than list price. Average sales price is $1.15M.
Central/South Phoenix isn't selling as quickly. Only one sold, and it took 277 days. There are however several pendings but the average DOM there is just about the same. Pending and Sold price per sq foot is much higher though, in the $380's. Average sales price is above $2M.
So, N Phx luxury homes sell faster but at a lower price and lower price per sq ft. It is tough to compare the areas because of the character of the historic neighborhoods vs the newer homes of N Phoenix but if you look strictly at the numbers, they give you a pretty good idea of what to expect.
Hope that helps!