Metro is not without its annoyances.  If you are used to a "traditional" smartphone where everything resides on the screen (and maybe you scroll to different screens) the Metro interface is going to feel cluttered.  It is a weird sensation when you scroll to the right that an entire new screen does not come up, but it is just one fluid motion of scrolling.  Also, while there is a reference spec for Windows phones, the system is not as closed down as the Apple iPhone is...

What?!

Yes, I actually value the closed down restricted interface on the iPhone.  Why?  Since Apple controls the entire ecosystem, app developers know exactly what hardware they are writing for.  Also, controling the entire system from computer to phone also allows for a better user experience as long as the user wants to stay within the defined ecosystem.  While I believe iTunes is a bloated and useless program, because I live the "Apple way" I never have issues with my computer or with the iPhone.  Microsoft has gone through great pains to try to have more control over the ecosystem, and WP7 does sandbox its applications so even if a virus or piece of malware was written for the phone, it would not be able to cripple the phone or other applications.