What are the pros and cons of each weapon?
The Hammer does high impact damage & has charged swing attacks depending on how long you hold the button down. Downside is that there's no defense to it at all. Even items that increase guard or add auto guard are voided.
Bowgun of course is great for shooting away at a distance & there are different types of ammo for different situations. Kinda cool that you can customize them as well. Downside is of course monsters typically don't keep their distance when attacking.
Great Sword is another hard hitting weapon like the hammer but you can actually block with it. Has a charged slash too. Only downer to me is that you move -really- slow while it's drawn. You'll find it more effective to sheath the sword & run over to a monster that moved across the area than to walk over there. Not the fastest swing either but with such a wide horizontal slash you don't always have to be facing whatever you were aiming at to hit it.
Sword & shield is light, fast attacking & has a shield. Not very strong so you'll have to strike fast & often to make a dent.
Haven't spent much time using the lance. From what I can tell it's a great stabbing weapon & the shield with it basically turns you into a walking phalanx. Think there's a forward rush attack in there judging from the times a lancer has bowled me over... Have to ask someone else here what the cons are.
Longsword... Only ever used one in the demo. Not sure where the power stacks up compared to the other weapons but it have some pretty cool combos(with practice) & a Spirit Slash special attack. Doesn't block but has side & back step evade-slashes. Only downers I can think of for now are that you don't get the most out of it by spamming one button & the one Spirit Slash combo I could do in the demo ends with the hunter auto-sheathing the sword. Looks cool but kinda stupid if the boss ain't dead yet.
Switch-Axe is a transformable sword/axe. Axe mode has longer range & a nice combo or two. Sword is closer ranged but I believe the stronger mode. Cons? Sword mode runs out of gas when used too much & you'll auto change back to axe mode while the gauge recharges.