as stated above my question is to have a more detailed explanation of the differences about starting a game in adventurer or warrior mode.
the manual simply state more fighting with the second...
more of the same monster? same game but more difficult to survive?
playing as adventurer you level up slowly? other differences?
someone have a more detailed explanation?
what you thought is the best?

I find the answer myself with the faithful google ;)
here: http://www.angelfire.com/hero/tjekanefir/xeen.htm
Choosing "adventurer" or "warrior" has no effect on your experience points earned, nor on any aspect of the gameplay other than combat. If you play on "warrior," monsters have more hit points and take longer to kill. This does make the game tougher, but also makes combat more tedious. It's not as if you get cool new monsters to fight, or the monsters have better AI, or even that there are more of them (which might force you to change your combat strategy). Each battle just takes longer. I've written my walkthrough from the "adventurer" setting, but if you're playing on "warrior," the only thing that will change is the increased amount of time it will take you to finish each area, the increased amount of resting you will have to do between battles, and the increased incentive to play the game in the standard order, since trying to slog your way through an area that's slightly high-level for your party will take forever.
so I'll go for adventurer :)

Adventurer is easy mode, and you may find the game boring if you select it.

If all the challenge it adds is extra hit points for monsters, I kinda doubt the fun-enhancing factor of it. Thanks to the OP for pointing this out. I know I'll be picking adventure mode for sure now.

Well, it IS worth noting that after you've gained a few levels, and especially once you have some of the more powerful magical augmentations, many monsters will go down in the first round, thus not even scratching your party. So, if the monsters actually live long enough to hit you, the game would be a bit more difficult (particularly against certain asshole monsters like the power lich, against which an overwhelming initial strike is vital).
I might try warrior mode next time I play, just to see how much of a difference it makes. A 50-100% increase in monster HP might actually improve the game, but if it's several times multiplied, "tedious" would probably be a better word.

Warrior mode is normal mode, a little easier than MM3. Adventurer mode is far easier, there's no challenge in combat any more.

The game was balanced on the warrior mode. So it's not like they just added hp, but rather they play tested against it.

antifood i love your avatar

After completing MM2 and MM3, I'm now playing World of Xeen. I wanted to throw in my 2 cents on this topic. Without much thought I selected Adventurer mode rather than Warrior mode when starting my game. I have to say that I'm finding the combat to be FAR TOO EASY, as others have stated here.
I think the problem becomes more obvious playing World of Xeen as opposed to either 4 or 5 by itself. This is because you are exposed to twice as many creatures designed for a given level range as you move from one game to the other. Do yourself a favour and go with Warrior mode.
Does anybody know if there is any way of changing the mode somehow? Perhaps a hack to the save file if nothing else?

Actually, yes, there is a way, or will be once I write it. Good thinking!
edit: just whipped this together: http://www.rebirthofxeen.com/files/difficultyflip.rar
Must be run from a command prompt. Download and extract the exe into your World Of Xeen folder, and then run it as "difficulty X" where X is the save number. The difficulty level for that save will be flipped (warrior becomes adventurer and adventurer becomes warrior)
For the record, Warrior is "normal", while Adventurer gives +5 to hit chance and does 3 times as much weapon damage. There are no other changes anywhere.
For the curious, I also supplied the source code.

I'll be choosing Adventurer mode for this, as well. That will have to wait until I get done with M&MVI, though.

I really do recommend Warrior mode. The stats are balanced for Warrior and reduced for Adventurer, not balanced for Adventurer and raised for Warrior. Warrior is how the game was meant to be played and it's paced perfectly, while Adventurer goes by too fast and easily to really represent how good the game can be.

Awesome! Thanks so much WizardStan. I'll give this a go tonight probably.

Ah, should also note it only works on the disk version. CD version uses different names for its save files which I didn't take into account. It'll also work with just Darkside, but not Clouds.

Warrior is easy mode, Adventurer is very easy mode. :-)