I say, unless you are using SQL 2005, don't switch.  The new tools got a TON of bugs.  What happened to the "script database objects" feature?  I gotta do it all separately per object now?  Why does SSMS not save my password change when I change the password for the login on SQL Agent Properties / Connections?  Why does SSMS use so much damn memory on my machine, and leak memory too? 

My advice:  Stay with EM until Microsoft fixes SSMS a bit more.  SSMS is a powerful tool, just not a quality powerful tool.... at least yet.