I've been watching the NBA for over 25 years, and I feel pretty confident in saying that it's harder to be a top 5 player in the league right now than it's been in that time span. Here's a list of six guys any of whom (based on his play right now) would have been a top 5 player at any moment in that time span with three more at the end who would have been top 5 at many moments in that time span. That's pretty incredible to me, and their is no question in my mind that Westbrook is on that list. It can be painful watching him try to carry a bad team on his back when he struggles, but when he is playing well (which is almost every game), he's truly amazing.
-When Lebron plays hard, he might be the most complete player to ever play. Enough said.
-Curry is the best shooter I've ever seen and among the best ball handlers. He shoots a very high percentage despite taking extremely tough shots. His defense isn't great, but it's MUCH improved from his first few NBA seasons.
-Westbrook just came off a season in which he carried an otherwise bottom 3 NBA team to the playoffs by doing everything for them on almost every possession. It's actually similar to what Lebron did in his first stint with the Cavs (except Lebron eventually got to the NBA finals albeit in a much weaker conference).
-Durant, despite his injury troubles this year, can still put up 30 a night completely effortlessly and very efficiently, and he's become a much better passer, rebounder, and defender with the Warriors than he was with OKC.
-Nearly everything that was said about Westbrook can be said about Harden except he lacks a little of Russ's explosive athleticism. The main difference is that Houston had the chance to build a better team that was well-suited to play around Harden while OKC got left in a lurch with the Durant departure. Clearly Houston is a much better team, but it's not clear that Harden is the better player.
-Kawhi Leonard is a guy the advanced metrics love. He's off the charts on offensive and defensive efficiency. He's the perfect player in the Spurs system.
-Honorable mention: Chris Paul, Anthony Davis, Paul George