I love my Ruger also. I already have over 20 ARs of various makes and calibers, but when I was shown the Ruger I was truly impressed. I paid right at $660 after tax for a new AR-15 that is solid as a rock and I absolutely love the screw type delta ring over the traditional spring type. In addition, I also liked the ball detent quick detach point on the gas block.
The only thing I changed was the handguard, and I changed it out with a Colt double heat shield type I had lying around, since the Ruger one didn't have the metal shield underneath it.