After an essentially disastrous intro in the teaser trailer where she came off as thoroughly annoying, Bill had a rather fantastic debut in The Pilot. She got some great lines (the mind wipe line was priceless). As for The Doctor, Peter Capaldi was on fire. He really had a zest to his performance in this one. Overall, this was a nice humdinger of an episode to introduce us to a new Companion and get the whole ball rolling again.
Unfortunately, the spinoff Class put me to sleep halfway through.