Hmm. I thought it was a fairly mixed episode, but the strengths of it were very good.
I loved Clara wandering through the Tardis, and absolutely loved the library scene. I'm wondering if partaking of the Encyclopedia Gallifrey drops will show up later, and if they'll tease any more Time War info.
The monsters were shit. They weren't scary to begin with, the costumes were made in 10 minutes, and the big reveal was weak while not making much sense. Why would a melted/scorched version of themselves try to kill them?
The salvage team was pretty weak, too. Not too bad at the beginning, but they didn't get any stronger as the episode passed. They were nothing but a transparent plot device and bad attempt to connect disparate bits of stuff into each other - robots can feel, just like the TARDIS! Oops, they touched - and look at time reasserting itself!
I liked how they finally confronted Clara's main point for being there and things actually seemed to move forward.
And unlike the majority here, it seems, I really fucking love the ending. The Doctor is a goddamn Time Lord - going back in time (or through a tear) to make sure people don't die and shit doesn't go down is the exact sort of thing you'd do as a person who can travel through time. That The Doctor didn't even quibble about crossing his own time stream to save everybody made me actually believe he was a powerful being called a Time Lord that actually had some level of mastery over spacetime. He wasn't bitching about fixed points or entering a lengthy debate about spoilers, he just up and went "Well obviously solving everything by giving myself the answer is the right thing to do, because it SOLVES EVERYTHING." Then BAM, he did it.
It was one of the few times throughout all of the reboot's episodes that I've gone, "Fucking *finally* it feels like time travel is something The Doctor knows how to use to his advantage." Instead of, you know, being an emotionally crippled know-it-all with a hyperactive personality at the mercy of the TARDIS and her whims.
So, definitely points for making The Doctor feel like a powerful being, and points for flirting with Oswin/Clara stuff.
If only the monsters were better...