- Excellent, easy to use GUI.
- No Command line shit required to do stuff.
- Easy customization.
Actually, you got your assumptions wrong. Android has GREAT command line support. You can do pretty much anything, including send SMS and initiate phone calls using the command line. It is one of the things I love about it: I can do whatever the hell I want.
Also, regarding customization, that is only true in theory. Phone manufacturers (I'm looking at you, Motorola) go out of their way to stop people from customizing. So, unless you are hacking the hell out of your phone, customization is very limited.
The fact there are so many different GUIs out there, with any manufacturer using a different one - or even multiple ones - also doesn't fit your model.
The reason Android is taking such a huge chunk of global market is mostly commercial. It is easy for manufacturers to use, and relatively cheap. There are great apps out there, and it is well supported by developing houses. It has a very usable interface (GUI). It is not exactly easy but, as far as smartphones go, nothing is really easy - we are just so used to it we don't even notice.
Lets face it, Android was in the right place at the right time, and (most specially) with the right mentality. iOS is apple only, and you are SOL if you are someone else. Windows mobile was a piece of crap, the phone would lock down all the time, and you had to go anything through Microsoft. Either you had to do your own development (like Nokia did), or you were out of the market. Along come Google with Android. In the beginning, not such a great solution, but a much better option.
Me ? I'm just happy for it. I own 2 Android phone, my wife has one, my daughter another ... Heck, even my father has one.