I only watched a little so as not to spoil the game for myself but I liked what I saw and I must say I'm liking the new voice for Wheatley much better than the placeholder voice that everyone seemed to respond so well to.

Well I don't. I was fairly indifferent towards the whole Wheatley debate, but I liked Richard Lord's work MUCH more than this new one.

looking extreme

I gotta say I really love all the moving machinery you see throughout the video. It's incredibly cool to me and really makes the facility seem alive.

Merchant sounds great as Wheatley.
 
Maybe it's just me, but I'm finding a lot of great humour in these early videos. I love the excruciating yell he gives when he turns on his flashlight and the whole "they told me I would die if I ever used this". Funny stuff.
 
All in all, it looks really good.

Looks (and sounds) awesome. I can't believe there's only 5 and a half years until this comes out. Can't wait.
 

That clip doesn't show it but I love how they've implemented shadow mapping everywhere in Source engine now.  Really improves the look.