Probably the Spurs. Dull choice that it is.
Personally, I don't see the appeal in San Antonio. Parker 33. Duncan 39. Ginobili 38. Team is facing a rebuilding process in near future. Will be scrambling just to stay relevant during Aldridge's best remaining years.
I'd choose Phoenix if I were Aldridge. Younger talent. Bledsoe, Knight, Markieff, A.Len.