I don't like Unity (so far), but I can certainly see it as the glue that binds a broader strategy to capture a bigger share of emerging OS markets like tablets and smart TVs.
Unity isn't perfect, but the fact that Canonical are thinking long term and have an ambitious strategy should be commended.
Ubuntu's goal is the very oposite of that from the begining.
Any coder and keyboard-user can easily pick between an array of distros that will target just them, while Ubuntu set out to be "Linux for human beings" and this is just the approach they chose.
For instance, if you want to get to the calculator, I type calc. The first option is LibreOffice Calc. I have to either use the arrow keys or mouse to navigate to the calculator which is the second option. I know that If I type ca or cal, calculator is first, but I tend to type calc and it doesn't learn.
I also use VirtualBox. In gnome-do, I can start typing the name of my VM and I can launch it immediately. Using Super in Unity, I need to open VirtualBox first. Then start the VM through VirtualBox.
This is super annoying when you know what windows are open in which virtual desktop. I used to be able to switch to a virtual desktop and Alt+Tab quickly. Now, I need to cycle through all open applications and I'm screwed if there's more than one window open of that application. Lot's of wait time. Using the mouse isn't much better.
I've used Ubuntu since 7.10 and have loved it and recommended it up until Unity. Now I'm seriously thinking of switching. I've been hearing a lot about Linux Mint.
Opportunity cost. Canonical is a small company with limited resources. If they can achieve the holy grail of a common interface that works on the new emerging platforms, they can carve out a profitable market share.
After all, the Year of Linux on the Desktop is a ship that has sailed.