I've been working on an Aasimar Dervish of Dawn, hoping to capitalize on their favored class option and I found this comparison interesting. It takes into account only:
The BAB for each class.
The Weapon Training and Inspire Courage class features.
Standard generic combat feats taken at the earliest appropriate level for each class (see below)
Fighter
1st - Weapon Focus
4th - Weapon Specialization
8th - Greater Weapon Focus
12th - Greater Weapon Specialization
Dervish of Dawn
1st - Weapon Focus
5th - Arcane strike
Obviously we aren't taking into account the relative attribute which would reasonably be equivalent for both characters nor are we taking into account additional Fighter feats or Dervish spells (like Dance of a Hundred Cuts). I thought it a fair comparison and was surprised by the results, considering all of the other things the Dervish can do:
1st level
Fighter +2 attack / +0 damage
Dervish +2 attack / +2 damage
5th level
Fighter +7 attack / +3 damage
Dervish +8 attack / +6 damage
10th level
Fighter +14 attack / +5 damage
Dervish +14 attack / +9 damage
15th level
Fighter +19 attack / +8 damage
Dervish +19 attack / +12 damage
20th level
Fighter +25 attack / +9 damage
Dervish +23 attack / +13 damage