Quarantine: I like the concept. I realize it was powered it up on request, but as it stands it's pretty broken IMO.
Will I take a 2 VP penalty in order to get access to $3 laboratories? Heck yes I will, even without the option to power it up. The ability to switch it to +buy or +coin on demand pushes it beyond "great". I would probably open Quarantine/Quarantine, race to get 8-10 curses on my mat if uncontested. I'm inclined to think the game would devolve into rushing quarantine, piling curses, piling quarantine, and then a complicated dance with duchies and provinces. (Like Rebuild, it'd still be pretty fun for a few games, though.)
GeeJo's version using tokens is a little more balanced, especially if it's competing with a lot of Adventurers cards. I'd still probably Quarantine/Quarantine anyways.
Poisoned Well: oh my word, you're evil. I love it.
Relief: also great. Great given the set (we've all been in brutal slogs before), but also works well in engines. (Come to think, it's very much like a proto poor house)