The choice of colors and gradients look terrible. They made iOS look worse. They swung too far away from skeuomorphic design. Even the art on the icons, without considering the colors, look like an amateur drew them. Look at the SDK icon: http://i.imgur.com/JXw7KQA.png That is ugly. So is the iTunes icon, so is the Safari icon. Not a fan.
I like the overall new style, however a bit of redefining here and there would be good, like some of the icons. Great update.