I wasn't playing when the original Conspiracy set was released, and had never really looked at the format. The release of this new set was a good opportunity to try it out, though. I went to one event at Big Kidz Games on Friday night, and another out at The Gaming Warehouse on Saturday afternoon.
The draft process for the Conspiracy format is different from normal MTG drafting in that some of the cards actually affect the draft process. Some let you look at what other people are drafting, some can affect the other cards that you draft, some have different power levels based on when you draft them (generally, better if taken late in the current pack). I enjoyed the process during these events, but I'm glad that all that added complexity is the exception, not the rule. It would get pretty tedious if every draft required all the extra bookkeeping that you need for a Conspiracy draft.
The signature mechanic of the Conspiracy format is the Conspiracy card type, which you put in play at the beginning of the game. The effects range from added abilities for a particular creature in your deck to changes in the basic game rules. One Conspiracy even turns deck construction on its head by prohibiting basic lands, instead allowing the player to sacrifice cards in hand to get special lands. This set added another signature mechanic, the Monarch, which is a title that moves from player to player as the game progresses and gives special abilities. Conspiracy cards are generally only used in the Conspiracy format, but the Monarch can be used in any format where the cards are legal - I expect Commander players in particular will get some use from it.
The actual gameplay in my two events felt very much like most free-for-all multiplayer MTG games. Everyone put out a bunch of creatures, but mostly didn't do much with them for fear that other players would take advantage of their lowered defenses. When one player got an obvious advantage - a big flyer, lots of card drawing, a powerful enchantment - the rest of the table ganged up on them. In both of my events, the players with the best early cards died first since they were seen as the early threats. The eventual winners started out more slowly, and eventually built up just a bit more power than the other remaining players. The Conspiracy format mechanics affected how the game was played, but not the way that these free-for-all multiplayer games generally play out.
I had a good time with these Conspiracy: Take the Crown events, but I don't know that I'd go out of my way to play more. A nice change of pace from normal drafting, but not something I'd want to do regularly.
