The flaw with the previously posted damage breakdown is that it only factors a margin of the damage enhancements existant in the game.
To break it into an actual build and compare the different weapons:
Dwarven level 20 barbarian, DA
Code:
Brb20 Dwarf Build
TWF TWF Fighting Style
Weapon
DA DA Weapon Type
0 0 Extra Critical Threat Range
3 3 Extra Critical Multiplier (F-Berserker bonus)
Yes Yes <Element> Burst
Yes Yes <Element> Blast
No No <Alignment> Burst
No No <Alignment> Blast
Base Damage
9 9 Weapon base damage
5 5 Weapon modifier
27 13 Strength
8 8 Power attack
2 2 Frenzied berserker set
2 2 Shintao monk set
2 2 Racial damage enhancement
9 9 Song
1 1 Prayer
65 51 Total Base
Effects
7 7 Holy
3,5 3,5 <Element>
21 21 Vicious
2,5 2,5 Slicing
1 1 Force ritual
35 35 Effects Total
100 86 Total Base With Effects
Critical Hits
6 6 Seeker
2 2 Critical threat range
3 3 Critical multiplier
195 153 Base critical damage
35 35 Effects
11 11 <Element> Burst
11 11 <Element> Blast
0 0 Alignment Burst
0 0 Alignment Blast
14 14 Natural 20
18 18 Total seeker damage
22 22 Critical Effects
270 228 Critical Total
0 0 Attack 1
100 86 Attack 2
100 86 Attack 3
100 86 Attack 4
100 86 Attack 5
100 86 Attack 6
100 86 Attack 7
100 86 Attack 8
100 86 Attack 9
100 86 Attack 10
100 86 Attack 11
100 86 Attack 12
100 86 Attack 13
100 86 Attack 14
100 86 Attack 15
100 86 Attack 16
100 86 Attack 17
100 86 Attack 18
516 432 Attack 19
530 446 Attack 20
137,3 117 Average Damage
Mob Immunities
0 0 Fortification
0 0 Damage reduction
0 0 Elemental resistance
Relevant Attack Data
5 5 Minutes lapsed
0 0 Number of haste boosts
0 0 Tempest/ Zeal/ Capstone
0 0 Haste boost
0 0 Number of Smites
0 0 Divine Sacrifice Interval
No No Superior TWF
No No Quick draw
Attackspeed
0 0 Number of haste boosts used
83 83 Normal
107,68 107,68 Haste/ Other
107,68 107,68 Haste/ Other/ Boost
538,42 538,42 Total Amount of Attacks
73925,2 62995,26 Total Damage
27384,09 Damage/M
246,42 209,98 Damage/S
456,4 Damage Per Second
Barb Critical Hit (19-20)
6 6 Seeker
6 6 Critical multiplier
390 306 Base critical damage
35 35 Effects
27,5 27,5 <Element> Burst
27,5 27,5 <Element> Blast
0 0 Alignment Burst
0 0 Alignment Blast
14 14 Natural 20
36 36 Total seeker damage
55 55 Critical Effects
516 432 Critical Total
Dwarven level 20 barbarian, Khopesh
Code:
Brb20 Dwarf Build
TWF TWF Fighting Style
Weapon
Khopesh Khopesh Weapon Type
0 0 Extra Critical Threat Range
3 3 Extra Critical Multiplier (F-Berserker bonus)
Yes Yes <Element> Burst
Yes Yes <Element> Blast
No No <Alignment> Burst
No No <Alignment> Blast
Base Damage
5,5 5,5 Weapon base damage
5 5 Weapon modifier
27 13 Strength
8 8 Power attack
2 2 Frenzied berserker set
2 2 Shintao monk set
9 9 Song
1 1 Prayer
No No Bladesworn
59,5 45,5 Total Base
Effects
7 7 Holy
3,5 3,5 <Element>
21 21 Vicious
2,5 2,5 Slicing
0 0 Other effects
1 1 Force ritual
35 35 Effects Total
94,5 80,5 Total Base With Effects
Critical Hits
6 6 Seeker
4 4 Critical threat range
3 3 Critical multiplier
178,5 136,5 Base critical damage
35 35 Effects
11 11 <Element> Burst
11 11 <Element> Blast
0 0 Alignment Burst
0 0 Alignment Blast
14 14 Natural 20
18 18 Total seeker damage
22 22 Critical Effects
253,5 211,5 Critical Total
0 0 Attack 1
94,5 80,5 Attack 2
94,5 80,5 Attack 3
94,5 80,5 Attack 4
94,5 80,5 Attack 5
94,5 80,5 Attack 6
94,5 80,5 Attack 7
94,5 80,5 Attack 8
94,5 80,5 Attack 9
94,5 80,5 Attack 10
94,5 80,5 Attack 11
94,5 80,5 Attack 12
94,5 80,5 Attack 13
94,5 80,5 Attack 14
94,5 80,5 Attack 15
94,5 80,5 Attack 16
253,5 211,5 Attack 17
253,5 211,5 Attack 18
483 399 Attack 19
497 413 Attack 20
145,23 122,13 Average Damage
Mob Immunities
0 0 Fortification
0 0 Damage reduction
0 0 Elemental resistance
Relevant Attack Data
5 5 Minutes lapsed
0 0 Number of haste boosts
0 0 Tempest/ Zeal/ Capstone
0 0 Haste boost
0 0 Number of Smites
0 0 Divine Sacrifice Interval
No No Superior TWF
No No Quick draw
Attackspeed
0 0 Number of haste boosts used
83 83 Normal
107,68 107,68 Haste/ Other
107,68 107,68 Haste/ Other/ Boost
538,42 538,42 Total Amount of Attacks
78192,19 65754,66 Total Damage
28789,37 Damage/M
260,64 219,18 Damage/S
479,82 Damage Per Second
Barb Critical Hit (19-20)
6 6 Seeker
6 6 Critical multiplier
357 273 Base critical damage
35 35 Effects
27,5 27,5 <Element> Burst
27,5 27,5 <Element> Blast
0 0 Alignment Burst
0 0 Alignment Blast
14 14 Natural 20
36 36 Total seeker damage
55 55 Critical Effects
483 399 Critical Total
Conclusion
Khopesh: 480
Dwarven Axe: 456
480/456=5,2% more dps for the khopesh.
The Khopesh uses a feat, whilst the Dwarven axe uses 12 APs. Both about the same worth depending on build / class.
If the khopesh user would be a WF with maxed PA enhancements, he would have ~498 dps, ~9,2% more dps. (though less to hit).
It really all boils down to what you prefer, and what class / build you're playing, and what quest you're playing.
In most situations however, the Khopesh will be ahead.
EDIT:
Same builds vs 50% fort
DA
Code:
Brb20 Dwarf Build
TWF TWF Fighting Style
Weapon
DA DA Weapon Type
0 0 Extra Critical Threat Range
3 3 Extra Critical Multiplier (F-Berserker bonus)
Yes Yes <Element> Burst
Yes Yes <Element> Blast
No No <Alignment> Burst
No No <Alignment> Blast
Base Damage
9 9 Weapon base damage
5 5 Weapon modifier
27 13 Strength
8 8 Power attack
2 2 Frenzied berserker set
2 2 Shintao monk set
2 2 Racial damage enhancement
9 9 Song
1 1 Prayer
No No Bladesworn
65 51 Total Base
Effects
7 7 Holy
3,5 3,5 <Element>
21 21 Vicious
2,5 2,5 Slicing
0 0 Other effects
1 1 Force ritual
35 35 Effects Total
100 86 Total Base With Effects
Critical Hits
6 6 Seeker
2 2 Critical threat range
3 3 Critical multiplier
130 102 Base critical damage
35 35 Effects
11 11 <Element> Burst
11 11 <Element> Blast
0 0 Alignment Burst
0 0 Alignment Blast
14 14 Natural 20
9 9 Total seeker damage
22 22 Critical Effects
196 168 Critical Total
0 0 Attack 1
100 86 Attack 2
100 86 Attack 3
100 86 Attack 4
100 86 Attack 5
100 86 Attack 6
100 86 Attack 7
100 86 Attack 8
100 86 Attack 9
100 86 Attack 10
100 86 Attack 11
100 86 Attack 12
100 86 Attack 13
100 86 Attack 14
100 86 Attack 15
100 86 Attack 16
100 86 Attack 17
100 86 Attack 18
335,5 286,5 Attack 19
349,5 300,5 Attack 20
119,25 102,45 Average Damage
Mob Immunities
50 50 Fortification
0 0 Damage reduction
0 0 Elemental resistance
Relevant Attack Data
5 5 Minutes lapsed
0 0 Number of haste boosts
0 0 Tempest/ Zeal/ Capstone
0 0 Haste boost
0 0 Number of Smites
0 0 Divine Sacrifice Interval
No No Superior TWF
No No Quick draw
Attackspeed
0 0 Number of haste boosts used
83 83 Normal
107,68 107,68 Haste/ Other
107,68 107,68 Haste/ Other/ Boost
538,42 538,42 Total Amount of Attacks
64206,7 55161,23 Total Damage
23873,59 Damage/M
214,02 183,87 Damage/S
397,89 Damage Per Second
Barb Critical Hit (19-20)
6 6 Seeker
6 6 Critical multiplier
227,5 178,5 Base critical damage
35 35 Effects
27,5 27,5 <Element> Burst
27,5 27,5 <Element> Blast
0 0 Alignment Burst
0 0 Alignment Blast
14 14 Natural 20
18 18 Total seeker damage
55 55 Critical Effects
335,5 286,5 Critical Total
Khopesh
Code:
Brb20 Dwarf Build
TWF TWF Fighting Style
Weapon
Khopesh Khopesh Weapon Type
0 0 Extra Critical Threat Range
3 3 Extra Critical Multiplier (F-Berserker bonus)
Yes Yes <Element> Burst
Yes Yes <Element> Blast
No No <Alignment> Burst
No No <Alignment> Blast
Base Damage
5,5 5,5 Weapon base damage
5 5 Weapon modifier
27 13 Strength
8 8 Power attack
2 2 Frenzied berserker set
2 2 Shintao monk set
9 9 Song
1 1 Prayer
No No Bladesworn
59,5 45,5 Total Base
Effects
7 7 Holy
3,5 3,5 <Element>
0 0 Tempest set
0 0 Henshin monk set
0 0 Sneak attack
21 21 Vicious
2,5 2,5 Slicing
0 0 Other effects
1 1 Force ritual
35 35 Effects Total
94,5 80,5 Total Base With Effects
Critical Hits
6 6 Seeker
4 4 Critical threat range
3 3 Critical multiplier
119 91 Base critical damage
35 35 Effects
11 11 <Element> Burst
11 11 <Element> Blast
0 0 Alignment Burst
0 0 Alignment Blast
14 14 Natural 20
9 9 Total seeker damage
22 22 Critical Effects
185 157 Critical Total
0 0 Attack 1
94,5 80,5 Attack 2
94,5 80,5 Attack 3
94,5 80,5 Attack 4
94,5 80,5 Attack 5
94,5 80,5 Attack 6
94,5 80,5 Attack 7
94,5 80,5 Attack 8
94,5 80,5 Attack 9
94,5 80,5 Attack 10
94,5 80,5 Attack 11
94,5 80,5 Attack 12
94,5 80,5 Attack 13
94,5 80,5 Attack 14
94,5 80,5 Attack 15
94,5 80,5 Attack 16
185 157 Attack 17
185 157 Attack 18
316,25 267,25 Attack 19
330,25 281,25 Attack 20
121,7 103,5 Average Damage
Mob Immunities
50 50 Fortification
0 0 Damage reduction
0 0 Elemental resistance
Relevant Attack Data
5 5 Minutes lapsed
0 0 Number of haste boosts
0 0 Tempest/ Zeal/ Capstone
0 0 Haste boost
0 0 Number of Smites
0 0 Divine Sacrifice Interval
No No Superior TWF
No No Quick draw
Attackspeed
0 0 Number of haste boosts used
83 83 Normal
107,68 107,68 Haste/ Other
107,68 107,68 Haste/ Other/ Boost
538,42 538,42 Total Amount of Attacks
65525,84 55726,57 Total Damage
24250,48 Damage/M
218,42 185,76 Damage/S
404,17 Damage Per Second
Barb Critical Hit (19-20)
6 6 Seeker
6 6 Critical multiplier
208,25 159,25 Base critical damage
35 35 Effects
27,5 27,5 <Element> Burst
27,5 27,5 <Element> Blast
0 0 Alignment Burst
0 0 Alignment Blast
14 14 Natural 20
18 18 Total seeker damage
55 55 Critical Effects
316,25 267,25 Critical Total
Khopesh: 404
DA: 398
404/398=1,5% more dps for the khopesh, vs 50% fort.