Dat title sequence. Damn. That is a thing of beauty.
In terms of the episode itself, I think it mostly does what a regeneration episode needs to do: it convinces the viewer that this new actor is the Doctor, and sketches out in broad strokes what this incarnation is going to be like. I kind of liked the way that this story sort of had Clara to stand in for the viewers who are new to the concept of regeneration and aren't sure what to make of the new Doctor, and Jenny, Vastra, and Strax to stand in for those viewers who are more familiar with the idea and are thinking, "Yes, he's the Doctor. Get over it." I think the last regeneration episode to actually have a regular character around who understood what was going on was Tom Baker's "Robot".
Part of me does wish that there was some way to do this without making Clara the clueless one. Because she's almost played/written as if she doesn't remember any of what happened last season. I think her reaction could have been slanted a bit more towards, "Okay, I totally understand about regeneration and I've even met a couple of the previous ones, but I'm still really freaked out when it's my Doctor that changes," rather than, "Why did the Doctor change?!"
I did really like the scene where Clara finally reconciles herself to the new Doctor. I thought that was really well played on both actor's parts, and really lovely.
As far as Capaldi's performance, I thought he demonstrated that he can cover the full range of Doctorishness. (There's a thought: part of the excuse for the post-regeneration wackiness is to allow the new Doctor to be run through his full emotional range.) I wouldn't say that I'm completely in love with this new version of the Doctor yet, but I like him, and I'm looking forward to seeing what he does in future episodes.
Compared to other new Who regen episodes, I'd say I didn't like it quite as much as "The Eleventh Hour," but quite a bit more than "The Christmas Invasion". Not a bad way to start the season.