I bought both Chivalry: Medieval Warfare and War of the Roses.
I saw a great comparison that to me holds very true. Chivalry: Medieval Warfare is to CoD: Modern Warfare as War of the Roses is to Battlefield.
CMW is got the gore factor going for it, but it's not very skill-based, it's really just a medieval arcadey kind of hack away at your opponents and hope you cut their heads off. WotR is much more skill based, the graphics are prettier in my opinion, and it requires teamwork and well placed shots. You can swing your sword just like in the Mount and Blade games where you determine the angle of your sword swing by the direction of your mouse.
WotR is much more realistic in both weapons/armor and fighting. It utilizes squad tactics and you can revive fallen teammates (in fact you need to if you want to win). WotR is simply the better game. The one fatal flaw for me is that WotR has a serious problem with NVIDIA GTX 580 series video cards and crashes every couple of minutes rendering the game un-playable. I'm playing more CMW right now, only because it works, not because I like it that much. If you like Mount and Blade, and want an experience that pays more attention to history, with a more complex combat experience, then get WotR.