Conversations with Dead People was a standout in S7. I like Principle Wood and I'm a fan of the way the series ended, but overall it's my least favourite, and I think it's because Spike-with-a-soul drags it down so much.
Regarding S6, I actually like it more than most people I think. I used to hate what they did with Buffy and Spike, but I think what saves it is when Buffy asks Tara if she came back from the dead different, and when Tara tells her she's the same Buffy just sobs. They explored a dark place in Buffy's life for a season and it really had some strong emotional moments. What happens between Anya, Spike, and Xander is much more unforgivable, imo.
Buffy and Spike never should have rekindled anything in S7. It diluted S6. But Spike is my least favourite character in both shows.