Windows' GUI shell is one big piece of shit. Unfortunately, that's what most of you are used to, like big majority of the people around the globe. Besides, functionality and looks are totally different thing.
Microsoft reverted the industry back for 10 years, they haven't innovated anything, and if situation remained like it was in 1990, only god knows what kind of monster personal computers we'd have today . Example;
This is a 386 based PC from 1990. It's running a single-user, single-task 16-bit operating system with a graphics shell add-on. It's among the top of Intel/Microsoft based computers of the time;
Now, this is a NeXT workstation, also from 1990. It's running a high-performance multi-user, multi-tasking UNIX-os, with a object oriented graphics shell. World Wide Web was invented at CERN on these machines;
As you can see, it's perfectly capable of running tons of processes, note the modern website surfing (Slashdot), among everything. While Intel/Microsoft PCs of 20 years ago aren't capable of doing any modern task, and people keep them for nostalgia reasons (like me), UNIX workstations of 20 years ago can still pull off a few tricks, even today.
If you need to know why Microsoft prevailed, it's because all the big UNIX players like Digital, HP, Sun, NeXT went battling each other for standards that should be introduced on personal computer market, while MS took market share year after year. Rest is history.
And, don't ever judge operating systems by their looks.