I personally believe napoleon was the best ever, even though he suffered defeats, the amount of battles he fought in and the difficulty of the battles he fought is extremely impressive.
Alexander the great also crossed my mind, although his military campaign wasn’t extremely long, and he did make some very questionable military decisions, even if he eventually won the battle.
The mongols as a whole were extremely successful, especially considering just how strong their enemies were, and how many of then that they fought against. They would be my first if all their fights were led by one person. However, although most mongol generals were extremely successful, individually, I don’t believe they hold up to some of the other candidates.
Julius caesar was extremely successful in almost all the battles he fought in, and whole he undoubtedly had very impressive military skills, (especially in utilising Roman fortifications) after reading about a lot of his biggest battles, it seems that luck played quite an important role in his success. He had plenty of situations where he was very close to losing, but managed to pull through. (Egypt and Alesia are good examples of this)
There are plenty more I can think of, but I can’t write them all here.
What do you guys believe?