Lets look at the history of UI changes. For Example the Macintosh OS has pretty much had the same UI over its 20 something year history grant there were big enhancements in the OS over the years the UI has pretty much been consistent.
Lets look at the windows OS. Since windows 95 the start menu has never changed with the exception of the windows LOGO on the start menu. So what is so wrong with the Iphone UI? If your bored with the iphone thats one thing but apple just isnt going to revamp the OS for you.
And lets see all HTC has is the Sense UI and i dont see millions of customers migrating over to HTC. Bring a real discussion with valid points not just spin