I'm probably a bigger fan of the Cities expansion over Leaders. In all honestly this expansion does add to the overall theme of the game, especially as it relates to players individual wonder board. Some leaders abilities are obviously stronger than others, so if you get stuck with some crumby leaders you'll be at a big disadvantage throughout the game. Lots of new icons to learn on all of the leaders cards as well.
I could take or leave this addition to a game of 7 Wonders.
If you're reading this you probably own and love 7 Wonders. If you are looking to add a little more complexity and strategy with the game you'll really like the Leaders expansion.
This expansion adds, you guest it, Leaders which can be purchased before you start drafting. The Leaders add benefits, some instantaneous and others end game bonuses like giving you an extra victory point for having 3 coins on top of the normal scoring. You also get another wonder which adds some cool Leader bonuses.
The expansion integrates seamlessly with the base game and can be taught to new players without having too much more explanation. It also doesn't add too much to the quick play time of the original base game. The art on the cards are beautiful and so is the new wonder.
Definitely a must buy if you have the original and want to spice things up.
My opinion of 7 Wonders is fairly low...but this expansion improved it quite a bit. It is still not a game that I will play that often.. but i will play it. Leaders add some reliable strategy to your game that makes you not so dependant on what other players choose to play. Each person gets 4 leaders of which they will play a maximum of three. One each round. They also have the option to discard for money.. but most times the ability is much better. If you buy 7 wonders... buy this as well.