MacBook Pro Power Button
My last MacBook Pro MacBookPro5,1 had an eject button on the keyboard and a power button off the keyboard, to the right and closer to the screen. My current Retina MacBook Pro MacBookPro10,1 has no eject button (because it doesn't have an optical drive) and has a power button in its place, on the keyboard.
When I first got this computer, the power button would simply bring up a dialog asking me if I wanted to shut down the computer. This was almost never what I wanted, it was likely an attempt to press the delete key that missed its mark. I found it mildly annoying.
After installing Mavericks, this behaviour changed: the power button would now sleep the computer. I was torn.
I liked having a way of sleeping the computer easily. When I step away from my desk, I don't necessarily want to leave my computer's screens on, wasting power, I don't necessarily want whatever I was working on last to be visible to anyone, and I certainly don't want someone to be able to access my computer. If I put the computer to sleep, when someone tries to wake it, they'll need my password.
However, it was still easy to hit this key by accident. When I did, having the screen to black, was surprising and confusing. Even if I realized right away what had happened, it would still take a few seconds to get back to where I was, which was frustrating.
Many people complained about this, and although I understood their complaints, I didn't share them completely because I did like being able to sleep my Mac.
After 10.9.1, however, the behaviour changed yet again in a subtle way. Now, a light tap of the key does nothing, you must hold it very briefly to trigger the sleep functionality.
This means that I can sleep the computer when I want to, very easily, but I never trigger it accidentally (or, at least, so rarely that it doesn't matter) to me.
This, to me, is the best of both worlds. It's great.
And yet, I still see people complaining, shutting off this feature using defaults.
I know you can't please everyone, but I also know that people are more vocal about things they dislike than things they like, so I'd like to come out in support for the current behaviour. As of OS X 10.9.1, I think the Power Button in Mavericks works just fine, and I'd like it to stay that way.