Pretty good. Spent more time looking at the videos (which annoyed me, whoever was playing sucked pretty bad), but it was good.
Actually, I got my roommate into Metroid Prime recently. It's been fun, him playing and me doing stuff on the computer, both of us making hilarious commentary, but watching him play I realize how good I am at the game. I know every nuance, every enemy, I know what every sound means and if there's an enemy and where that enemy is, I know how to solve every puzzle, and I am an amazing combatant (and usually go for dramatic effect; combat can be so freakin' awesome in Prime if you put forth a little extra effort).
So it'll be fun losing that advantage (or most of it) in Echoes, and working to regain it.