I played the trial downloadable version of this game until it expired and couldn't wait for the full version to arrive, in fact Mount & Blade is singularly responsible for bringing me back to playing PC games; I don't think I've bothered since 2006 when I came across EVE ONLINE.
Point of reference for many with M&B will be that graphically the game resembles the Elder Scrolls games Morrowind and Oblivion, but to tell the truth it is there that all similarities end. M&B is essentially an RPG/strategy hybrid - it contains elements of both kinds of games, with a wonderful emphasis on combat: large-scale battles in this game are something to be experienced (if medieval combat is your cup of tea, anyway) it's nothing but exhilarating to charge across battlefields hacking at enemy soldiers from horseback, I've actually found myself assuming a sort of riding position mid-gallop in front of my monitor whilst playing - the combat is where the game comes into its own, I don't think I've ever played a game where this was so detailed, for instance; it's not uncommon to find yourself on foot in the midst of fighting and witness a friendly mounted knight galloping past and slaying unseen foes for you, other nice touches include the way arrows stick in your shield (and stay there), regardless of whether you're wearing it on your back or not.
Combat isn't the entire game though, as you progress you acquire fiefs and it is up to you to garrison and protect them from bandits, etc. There's so much to do in the game that you're not likely to get bored quickly. However, there are a few negative points: the dialogue isn't great, but it's a small part of the game. There's also a few annoying bugs, but these are quickly & easily sorted with downloadable fixes.
Oh, and the music's really good too.
A quick word on the visuals: many are quick to turn tail and run if the game has even a hint that the graphics are anything but next-gen. I've noticed that detractors are keen to note this with M&B, but bear in mind this is an independently developed game from the ground up and in all fairness, graphical updates have already been made available for free download, as have a dozen mods that set the game during the hundred-years war and Britain in 1297.
This game is an exercise in substance over style that should keep you hooked for ages - utterly recommended and the best game I've played in years.