It has certainly appeared that way. OKC is more "battle tested" etc...etc....
However, I went back and looked at actual records.
Utah and Dallas had identical records; however Utah finished the year 7-3, while Dallas slipped in playing .500 ball. On paper, at least, Utah would have looked to be the tougher matchup at that point this season. Now on the court, Dallas certainly appeared to be the tougher draw (at least in the first two games.)
As for the LA teams; they were separated by only one game in the RS; and finished the season with a similar run. "The Clippers were hurt" is a common argument; however, those Clips, ostensibly more hurt, closed out Memphis on the road before being made to look inept in the WCSF.
It wasn't the playoffs, but the Spurs played that same Laker team twice during this current winning streak, while both teams were battling for playoff position, and beat them like a red headed step child both times.
My point is, obviously the Spurs have not been strained or had to flex real hard the first two series; but I'm not sure if they had been on OKC's side of the bracket it would look much different.
Look at the facts, the run, the margin of victory that exists regardless of opponent or venue. I think, as hard as it might be for us all to wrap our minds around, that the Spurs are just THAT GOOD.
It's not about matchups, this player against that player. It's about team. After all we don't predetermine who is going to be the best basketball player simply by the sum of his parts (most of us, anyway). We don't measure his arms, biceps, legs, etc... and determine that this guy will beat that guy; we look at how the guy actually performs on the court. Otherwise, David Robinson would be the best basketball player ever; God got serious when he designed him. Robinson would certainly be a better player than Tim, right? Just look at them!
I've watched the playoffs, and been very impressed with OKC's players; they make a ton of shots, many difficult. They have many more highlights than the Spurs. Step back fadeaways, follow slams; all very impressive. The Spurs don't make a lot of tough shots because the Spurs almost never take tough shots. Their team and system get open looks constantly. Expect Oklahoma to have to make many more tough, or uncomfortable shots during this series; it's what Pop/the Spurs do to opponents. At the end of the games, in crunch time, when Durant and Westbrook have each played more than 40 minutes, expect the Spurs to get exactly the shot they want. Up until Sunday, after all, I don't know how many times I had heard that CP3 was the best closer in basketball.
The Spurs just finished making two playoff teams look young, inexperience; not ready for the playoffs. I expect, to a lesser degree, they're about to do it again.