Considering trading my widgets for live tiles...

I've been an Android user for the past two years and I'm looking to try something new. I have an SGSII with T-Mobile right now and am underwhelmed by the current T-Mo WP7 crop. Should I consider going with an unlocked Lumia 900, Titan II or tough it out with the Radar or the HD7? Also, if there are any former Android users who made the switch how was the transition for you? What do you miss? What do you like most about WP7?