Spin The Bottle. Not only did I think it a lot funnier than TR, it also lacked the depressing background of Willow mind-raping people again, just a day after promising Tara not to. 🙁
I've always preferred "Tabula Rasa," simply because I prefer Buffy's series to Angel's. As far as "Spin The Bottle" being funnier, that's simply , to me at least, because the actual story isn't about the memory loss because of a spell gone wrong, but rather about the reason for the spell in the first place.
"Tabula Rasa" was a story about one person (Willow) attempting to manipulate or steal the memories of another (Tara), without that person's knowledge or permission, in other words, as it has been described above, mind raping them. "Spin The Bottle," on the other hand, is about one person (Lorne) attempting to RESTORE the memories of another (Cordy) with both her permission and knowledge.
Willow was attempting to use magic for personal gain, to steal something that she had no right to (Tara's memories) even though she attempted to justify herself by saying that it was for Tara's own good. Lorne was attempting to return something that belonged to Cordy (with no editing or manipulation, no censoring out of what he thought were any bad memories) something that it cannot be denied she had every right to.
"Spin The Bottle" was more light hearted and funny for the simple reason that that sinister element was not part of the plot line.