at first look, both are very similar, but there is big difference between them
1. His only one adventage is high max dmg, ed is average, no other usefull stats, and damn knockback, which makes in my eyes valuable of this martel very low - i would say you can get for it 50-70 fgs, if you will find buyer, what wont be easy with KB IMO.
2. This one got more adventages, higher AR and the most important 5%ml makes it very sexy, i would say its worth with this dmg and adds 150 fgs
greets