Themken: The first Mount and Blade is a bit limited in its scope but if you are fine with conquering Calradia one town and one castle at a time, then it is warmly recommended. Warband has more things in it but I found it too much and went back to playing the first game = a recommended game.
just a tip: I found the tutorial unrepresentative of gameplay.
I too currently favour the original Mount & Blade game, but in my case it is because it is stable and reliable whereas Warband has graphics corruption issues on AMD video hardware and too frequent random lockups so I wasn't ever able to fully get into the game and enjoy it. These issues might have solutions out there however, I didn't research it exhaustively. I know most people who play the series favour Warband out of the entire series so I must presume that it works fine for the majority of people who either are not using AMD video hardware or have found workarounds for the technical problems, and I hope to do so some time in the future as well.
My only other complaint with Warband which I presume is also common out there, is that if you played the first game and got deep into it you've been immersed into this world and its layout and lore, and in Warband it is the same land - but they completely redesigned the map and moved everything around which really threw me off and harmed the lore for me a bit. It would be like redesigning a game that takes place on Earth to move North America to be between Australia and Africa and have the US on the right and Canada on the left and rearrange just about everything for no clearly identifiable reason other than "just because". Since the 3rd game takes place under a completely different scenario it avoided that problem, and part of me wishes that they'd have just made Warband take place in a different land at a different time rather than rearrange all the locations from the first game. Sure, it's just a video game fantasy world, but part of the fantasy is seeing things as a real place as part of immersion into the world, and that's ripped right out when things are moved around for creative freedom or whatever. Why don't they make a Lord of the RIngs version of the game next and move Mordor to be right next door to The Shire. :)
Anyhow, I've rambled on about Warband offtopicly even though it is probably a fantastic game as it is made out to be.
I do have to give a huge multi-thumbs-up for Mount & Blade also though.