The thing that I noticed with Guest Stars at F&L was that they were played just like PCs. They didn't gain XP or PK, no. (But they skirted that last rule a lot, and did a lot of things that should have /invited/ people to PK them, but given their sheets, well.)
But, my main issue with them is that they /could/ and /did/ dominate plots. At one point, it felt like Luxor, the vampire staff, was just running a plot to show off the sheet of his vampire Guest Star.
Which just felt very meh, on top of his tone issues and inability to take any feedback on his tone, and playing favorites.
I liked the rest of the staff and the players at F&L. I would actually recommend checking it out, since I think people can enjoy it. Just not me, apparently.
Never tried Fate's Harvest because people I trust told me to stay away from anything with Spider involved. And I trust them, so.
The other games, never heard of.