the Spurs probably off the better opportunity.
San Antonio is a top five team in the league and would be adding an All-Star that fits well in their system.
Phoenix is a fringe playoff team with no three point shooting.
Occam’s razor and whatnot… Spurs are probably a better basketball decision.
One of the Suns selling points that SA doesn’t have is the chance to be the man in achieving something unprecedented. If Aldridge thinks he can pull it off and has enough confidence/ego/narcissism then the Suns still have a chance. Some guys want to be featured… have "their" team.