I've got the Orange Clockwork - managed to get the s version in large on sale for £920 from Drake Cycles in Leeds.
I'm still getting used to it, but my initial impressions are that for cross country its definitely faster; it climbs better (? larger footprint = better grip?), it climbs faster, descends faster (bigger wheels), haven't done anything too technical at the minute, but it feels responsive.
After moving from my old Cannondale F5 I can definitely say it feels different - not just in the speed.
The 26 wheels feel livelier when moving off, whereas with the 29er you are more aware of the additional angular momentum needed to get them rolling - but there is not much in it.
They are definitely different beasts, and while I loved my F5, I sold it last night (got £250 notes for it) and though I was sad to see it go, the 29er just feels better all round for me (and for my height) and I love getting out on it for a ride.