The S600 is one of the finest sprinklers ever made. It was designed by the same man who designed the PGP. I've seen them hold up for 20 years, and only require occasional cleaning. They are a little dificult for the novice to adjust, but still one of the best on the market. They have been in production well over 20 years for a reason, while RainBird seems to introduce a new and improved rotor every 5 years, and stop making heads like the T-Bird.