What has surprised me is this.
Lineup GP MIN Pace OffRtg DefRtg NetRtg +/-
Starters 10 99 95.8 93.5 92.7 +0.8 -4
Other 14 572 97.2 108.3 92.2 +16.1 +173
Total 14 671 97.0 106.1 92.3 +13.9 +169
The Spurs have been winning games via their bench strength. The starting lineup isn't doing very well but the bench is killer. A net rating of 16.1 is crazy good. That means the Spurs have the best bench in the league handily but the starters are underachieving and is only a bit better than average compared to other starting lineups.
In comparison our bench only had a net rating a bit higher than 1 because the bench defense is putrid.
However, in terms of net rating(11) we have the 5th best starting unit in the league and we play our starters together more than any other team.