Great multiplayer, singleplayer is lackluster
The singleplayer is lacking though. It's an improvement over the original's campaign to be sure, but it's still not nearly the same quality as some of the more popular mods, like Native Expansion and Prophecy of Pendor. I mean, maybe that's okay - the community for this game is absolutely fantastic, and no doubt the mod makers will flock to Warband, with its slick animations and various other improvements over the original engine, but it's kind of disappointing. The module system was recently released though, so we'll be sure to see a lot of very interesting mods.
The devs are very responsive to the community, which is part of what makes this an easy investment. The released version of the game was quite buggy, but they've released several patches already to balance things out. If anything, you are supporting a group of people who really believe in the product that they are releasing. It is rough around the edges, but if you can get past that you are in for a treat. Since it was released, I've played over 100 hours in the original game, and I can easily see this one being just as enjoyable.