I just finished the whole of it, and I have to say... Fantastic! Its obviously less of a regeneration story than "just another Doctor adventure", but its a fantastic one at that. Robot is more of a regeneration story than this is, but it doesn't work nearly as well as a story from almost any perspective. This one is, clearly, the best Dalek serial I've ever seen from OldWho - not better than Genesis, but the Daleks weren't the main drive of that serial, their creation was and, of course, Davros. Here, the Daleks are the villains, and they're as cunning as they've never been. I respect Terry Nation for his creations and his vast imagination, but IMO, he couldn't write convincing character interactions or nuanced behaviour into his scripts as well as Whittaker and Spooner do here. These Daleks have personality and distinct feel to them. The animation fortunately didn't ruin the feeling from their meeting with the Second Doctor that they DO know him, the DO fear him, and what he has to say about them, but they WILL carry on pretending they're servants. Clever writing for the Daleks - imagine that.
Of course, if I have a niggle, it'd be that, unlike Deep Breath (which seems to have borrowed the not-my-Doctor theme from this one the most), the companions don't turn to the screen and re-assure the audiences at the end. I thought I missed that.
Overall, if I had to rank it, it'd probably be one of my top favorites. Top 10? Sure! Top 5? Well... can it stand alongside latter giants like Genesis, City of Death and Caves of Androzani?
Probably. I'm so glad this was animated, and we can cross if off the list of unwatchable, lost stories.