I bought the game now year before about 1. A few months earlier I purchased from the same game designers Dominion (+ all major extensions) and was thrilled. However, this enthusiasm could not bring up to Kingdom Builder. As noted already in some reviews before the game is limited as a strategically the best tactic is no use if you pull (an unfavorable) Terrain card the wrong.
The first extension can in the game - save nothing, because the basic mechanics easy to complete is "restrictive" - in my eyes. I am of course aware that you just have to think a lot more through this limitation, however, a large portion of the tactics will end up reduced to card luck. In the last year I have maybe the game 15 - played 20 times, of which some parts with 2, some with 4 players.
What is bothering me to Kingdom Builder somewhat the lack of interaction of players. According to the manual should be on a 4-field play big game when you play a game for 2 players. Are not both players from confrontational, anyone can build small settlement, undisturbed by the other players. Even if the pitch is reduced to 2-fields is still too much leeway to wreak really "serious damage" to the players (where all actions again by the luck factor - are determined and limited - drawing cards).
I think it is not very surprising that the basic game was to have the last time for under 10 (without extensions), it is still apparently as lead on the shelves of retailers. I can see though that the game has a tactical component, however, is this - even with multiple games - pretty "lean" and extremely dependent on what terrain cards you draw.
Conclusion: There are better games and the "return to play" Feeling comes at Kingdom Builder just not right on.