Anne in the car on the way home (we were watching at a friend's) spotted certain similiarites with the Philip Pullman trilogy. These are explored further by communicator here and in comments to despotliz here.
Having just listened to (and watched where possible) the Dalek Master Plan, I really did think that Rose was going to go out into the void, like Katarina. Though I was happy enough with her being saved by Pete ex machina.
One of the kids watching with us muttered at 37 past the hour in that we had eight minutes left, and the plot seemed to be over. He actually stuck it out to the end but his two elder brothers fled as soon as (as spaced_oddity put it) Rose's make-up started melting.
Yeah, the very end went on a wee bit - but it's not the worst padding we've seen from Russell T Davies in his own episodes. The only bit that was really silly was cyber-Yvonne weeping (?oil?).
Edited to add: Anne asks, what about the Cybermen who were Cyber-ised on our Earth - surely they were unaffected by passage through the Void, and therefore shouldn't have been sucked in? But maybe the materials for Cyber-ising them were brought across?
In summary: Very good stuff, and very nearly great.