Jason Snell, writing for Macworld:
Beyond the system font, the most obvious visual change in Yosemite is that the gray light-to-dark gradient atop most windows is now much more subtle, so much so that I didn’t even register that I was looking at a gradient. In addition, the red, yellow, and green “stoplight” buttons on the corners of windows—the ones you use to close, minimize, or zoom that window—have been stripped of the shading effects that made them look like pieces of candy. They’re just flat circles now. (When you move your cursor over them, you’ll find the same X in the red circle and minus-sign in the yellow circle. The green circle no longer displays a plus-sign, however; instead, it shows the two-headed arrow that indicates full-screen mode. If you want to zoom a window’s size in and out, old-school style, you’ll now need to hold down the Option key before clicking the green button, or just double-click on the window’s title bar.)
Can I just say: ugh? This sizing behaviour is one of the things I hate most about capital-w Windows. Full-screen or nothing, baby! I mean, fine, if thats what you want or if you’re rocking an 11“ MacBook Air that’s cool. But one of things I love about my Mac — and one thing at which Microsoft’s product is particularly awful — is window management. When I click that green ”+" button my window expands only to the size it needs to be. What an amazing concept! And with features like Mission Control (I still lovingly call it Exposé) I jump to any window I want or any of my virtual desktops.
I guess what I’m really saying is… at least give me a check box?