Instant favourite, the smoothest rules (I could not have imagined a game with this complexity could flow so well and have a manual so easy to navigate)
Insanely good player interaction, at no time boring, and there's basically no downtime. Paying attention to other players is necessary and effortless. Paired with great rulebook and well defined order of actions, this made my first game flow incredibly well—even though the short scenario took over 6 hours. 2-3 hours in we all felt like we had been playing for 45 minutes.
True competitive co-op, nothing like terraforming Mars (which is co-op in flavor only). You generally want the company to do well while skimming a bit more off the top than your opponents.
And the game does not abstract away the horrible things you do. It's very clear that the players are not the good guys. Power is central to John Company, and not just in the sense of "might", although military strength s important—in the sense of political and economical power, unchecked except by those who would like that power for themselves.
Favourite old game discovered this year: The King is Dead. An area control game with restrictions that interact in very interesting ways.
Perennial favourites:
Orleans - the most played game at my weekly board game group. Worker placement and deck building combined.
Concordia - a great resource collection game, plays well from 2-5 players with no rules changes
Hansa Teutonica - brilliant worker placement game. Looks bland, plays well, and now comes in a well-priced box with all expansions.