I finished season five today and I loved it. Might be my favorite finale beside Season Two. Damn, the latter half of this season Whedon just liked to rip your soul out with sadness. "The Body" is probably one of the best episodes. It's not something I'd go and rewatch anytime soon due to its nature, but damn it if it wasn't great directing and writing. This episode pretty much shows Whedon has as much as a knack for directing as writing. It was nice to see a medium so writer's driven be just as involved in terms of directing.
"Restless" was great because it wasn't your typical "Let's do some crazy ****" finale. It was a nice respite considering Adam wasn't even the main villain for the entire season, so a finale that wasn't off the wall exciting was appropriate. But it was just as interesting as an exciting finale would be otherwise.
Whedon really captured the bizarre world of dreams while still being thematic. I mean the man with the cheese on his head. Dah fuq? Genius though.
And my favorite episode thus far is either "The Zeppo" or Spike's first episode. Xander being my favorite character and all, "The Zeppo" is such a genius episode about him.
I gotta say, Spike's arc if pretty damn convincing and highly entertaining. He's one of my favorite things about the show and his change is part of it. At first I was worried that he'd be "neutered" to appear just for the sake of it, but it actually makes sense and is endearing to him as a vampire while his acts are of humanity without a soul. He's more interesting than Angel for me anyway.
If we're talking about spin-off's I'd be perfectly content with a Xander/Giles/Spike road trip television series or tv movie. Just three of my favorite Buffy characters riding along the country having to solve **** while bickering is entertaining to me.
And I'd like to get to Angel when I have time. But first I want to finish Buffy then get onto Firefly.
Your thoughts on the latter half of S5 and "The Body" in particular basically mirror my own. I loved it, thought it was brilliant, but man I can never bring myself to re-watch that episode. It's just so brutal.
And I think most of the fandom seems to agree with you on Spike vs. Angel. I actually personally prefer Angel, but that's because I felt like the writing of Spike in the later seasons felt like pandering to the fandom to me, so it always rubbed me the wrong way. That said, I'm not much of a "shipper" with this show, so I preferred Buffy when she was single. That goes for Spike and Angel, too. I enjoyed them all as individuals but never shipped them with each other.
That said, I think if you were to watch
Angel the series, you'd develop a MUCH better appreciation for Angel as a character because, well, he just
became a better character out of necessity to carry his own show. I agree based on his appearances on Buffy, he wasn't really anything special. But I do agree with what people are saying here about
Angel the series. It DOES rival
Buffy in quality in a big way, and even surpasses it in some aspects. For example, I think the main arc of S2-S4 of
Angel is probably the most ambitious and epic arc any Whedon show has ever done. The character arc of Wesley on that show is also probably the best in the Whedonverse.
Ultimately, what I tell people about
Angel is that it's a wholly different show - it's not a coming of age story, because its main character is 250-ish years-old with centuries of horrible, horrible baggage. It's more of a redemption saga with A LOT of existential exploration and tragedy, and ultimately just feels like a more "mature" show than
Buffy, which makes perfect sense given the differences between the two protagonists.
Angel just feels a bit more Shakespearian to me. And when I compare the two shows, I always say
Buffy has the stronger and more memorable individual episodes, while
Angel has the better arcs. Ultimately, I prefer
Buffy because those individual episodes are pure genius to me (and yes, despite the fact that I hate Xander, I still share your love of "The Zeppo"), so I can easily pick an episode to re-watch on a regular basis, and I guess I can relate to Buffy better, having been a teenage girl once myself. But
Angel definitely stands on its own as a great series. If you do watch it though, just know you have to power through the very lackluster 1st season to get to the good stuff. The show had to find its own identity first, and that took a little while. But once it does, it's great, and the final season of that show>>>>>>>the final season of
Buffy.
Also, as I'm sure you've already noticed, it crosses over with
Buffy a lot, so there's that.
t: The episode after it, "Tabula Rasa" is also kind of a classic, too. Two episodes of pure gold if you ask me.
The last one actually had Jeremy Renner in it which was a great episode in itself. 
