I think a lot of people dont realize that GLB is a polearm. Yes, a polearm. That means that the polearm animation is being used on the GLB. Some of you may be ignorant bastards who havent payed attention to this, but the polearm animation removes about 20 length on a weapon. The weight and speed difference on these 2 are negligible, through I have heard that the 2 hand animation is faster than the polearm one, though I am not sure about this.
Great Long Bardiche
price 13,705
weapon length: 155 (135 effective)
weight: 3.8
difficulty: 18
speed rating: 87
weapon length: 155 (135 effective)
thrust damage: 18 pierce
swing damage: 46 cut
slots: 2
Can't use on horseback
Unbalanced
Bonus against Shield
Flamberge
price 18,777
weapon length: 152
weight: 4
difficulty: 18
speed rating: 86
weapon length: 152
thrust damage: 24 pierce
swing damage: 46 cut
slots: 2
Can't use on horseback
Can't sheath
So as we can see we have the differences: flamberge costs more, flamberge is 20 longer (a lot), GLB has bonus against shield, and the GLB is unbalanced which makes it impossible to duel with.