I don’t like the Unity shell, but I’m willing to give the Ubuntu developers the benefit of the doubt. Though I’ve been tempted to go storming back to GNOME, I’ve ultimately decided to have patience. There are design flaws. People are working on them. Things will get better. I also don’t make empty threats to move to Canada whenever my preferred U.S. Presidential candidate loses an election.
However, there is one flaw in Unity’s design that I can’t not mention: the retractable dock interferes with maximized windows. The left-hand edge of a fully maximized window overlaps its real estate. If you mouse over to this side (e.g. to hit the back button in a browser or open an application’s File menu), the dock will slide out and cover up the part of the application you’re trying to use. I can’t tell you the number of times I’ve tried to close a window and opened “Dash home” instead. In practice what you end up doing is racing the dock. It’s like playing the child’s game where you take turns flipping playing cards face up and race your opponent to be the first to slap the jacks. Except I don’t want my operating system to be my opponent, and I don’t want it to slap my hand.
You can’t move the Unity dock out of the way by pinning it to the bottom of the screen. Nor can you make it permanently visible, so that maximized windows never overlap it. The workaround is to never work with maximized windows, instead delicately stretching non-maximized windows so that their left hand edge is just beyond the Dock’s danger zone. But the whole point of maximizing is to obviate this manual resizing. The maximize window button in Unity is effectively broken.
The Unity dock is clearly an imitation of the OS X interface, which is not in itself a bad thing, but Apple does it better. In OS X this overlap race condition happens at the bottom of the screen by default, which is much more tolerable because you spend less time at the bottom of a window than you do in its upper left-hand corner. And if it really bugs you, you can make the Apple Dock non-retractable, trading a bit of screen real-estate for the assurance that you’ll never get your hand slapped. Unity is getting there, but there are still a few more ideas from Cupertino that it needs to steal.