- What does it contain?
- How does each component affect the base game?
- What improvements/advantages will it offer me?
Merlin's company comes with a few different things:
The 8 new knights can add some variety as you learn to use their powers. MC lets you play with 8, and if you really want to you can probably play with 9 or 10 without any major issues. The loyalty cards allow for as many as 3 traitors, although this substantially affects the difficulty level.
The new black and white cards are the real core of the expansion. There are plenty of new special blacks and whites, as well as enough standards to balance things out. The new threats and powers added by these cards are what really makes the game more interesting and fun.
The travel deck is basically just a cool way to make the game harder. Every time you move to a new quest you have to draw a travel card, most of which do bad things, although sometimes they will bring Merlin to your side and let you draw more white cards while on a quest. This adds a fair bit of tension and difficulty and makes the knights think very carefully about when to move around the more treacherous roads around Camelot.
Overall the expansion adds more variety, letting you add more players, choose different knights, play with 2 traitors, and use the travel deck to tweak the difficulty level. I'd highly recommend it if you play SOC a lot as it makes the game a lot more interesting. :D