This is an extremely challenging, interesting expansion set! You will need a copy of the Power Grid base game to play. This expansion includes a durable, full color double-sided game board (one for China, one for Korea), and two pages of rules. There is no storage box included. One expansion set will fit inside the base game more or less. If you need an extra storage box for your Power Grid expansions, the Power Grid - Brazil/Spain & Portugal Expansion set comes in one large enough to accommodate all (or most) of the expansions available at this time.
Korea has two different resource markets for North and South, and you must announce which one you are going to purchase from each round. The South is tightly packed industrial with medium to low connection fees (including four cities clustered together with no connection fees!). The North is a wasteland with long distances and high connection fees. The new rules amount to maybe half a page, and that's to explain the two resource markets. It's an extremely fun map, and I can see why everyone says Korea is the best one so far. Korea is safe and not too complicated to introduce newbies to Power Grid. I give this map five stars, and it alone is reason enough to buy this expansion even if you never play China.
China introduces the concept of a planned economy and has a page and a half of new rules that take a bit of getting used to. It is a low money game for a long time with crappy power plants (and there are one less for auction than the number of players, and the plants come out in numerical order with no futures market). It will take longer to play than a normal game, so factor in maybe an extra hour. The map has the industrialized coastal regions (Hong Kong, Shanghai, etc.) with a mix of high, medium, and low connection fees, and then there is the vast western agricultural zone with ridiculously super-high connection fees that will make you weep. Do not introduce newbies to Power Grid with China under any circumstances! They will hate it. This is a hardcore version of the game that starts off as a real slog and not much fun, but then picks up as it goes along. Mid-game to end game is just as much fun as a regular game. I don't think China is a map that will be played often by my group, and only with the right mix of dedicated players. That said, winning China really feels like an accomplishment, considering how hamstrung you are at the start. I give China three stars, maybe three and a half.