Whether the OS looks good or not is, of course, subjective. But it's hard to argue that Apple have innovated all that much from the original release:

http://www.lookingforiphone.com/wp-content/uploads/2011/05/I...

to the latest:

http://admintell.napco.com/ee/images/uploads/appletell/Iphon...

By comparison, look at Android's first release:

http://www.scientificamerican.com/media/inline/91052290-CE47...

Compared to ICS:

http://hotcellularphone.com/wp-content/uploads/2011/10/Andro...

WP7 is difficult to compare because it was effectively a complete reboot of the entire OS, but still. Apple's visual style has not changed much since 2007.