It's good to see Spike finally in this season, but he seems an odd choice for exposition. Usually, when he's "figured something out," as he often says, he's actually way off track. But he told it in his style, and without spilling the Madeira. Then one-upped Giles wonders how he didn't see it - indeed, the universe has shifted!
I probably am the only one who had no desire to see either Bangel or Spuffy in the comics, but if you're going to have it, don't have Buffy bouncing back and forth like a tennis ball, to quote Spike! Have her pick one or the other, go boy-boy-girl threesome (without Charlize Theron), or just drop it already. Showing her fantasizing about Spike right after she's been with Angel is just ridiculous, afterglow or not, and too, well, nakedly pandering to both shipper fandoms, so no one feels left out. And all this when she was after Xander just a little while ago. It makes Buffy seem like a libertine, which isn't fair to the character.
Spike's gleeful "Look at that!" at the sight of the crater formerly known as Sunnydale was fun. It's clearly better even than destroying Big Ben. (And I think I just caught onto this as symbolism for Spike ruining Angel's moment?)
The new dimension referring to Buffy and Angel as parents seems off. Wouldn't they be its gods, more like?