Great question. For the most part, Beowulf's character is similar to other epic heroes like Achilles, Aeneas, and Hector. Like these three men, Beowulf is a courageous and skilled fighter who leads his warriors in battle. Also, like many other epic heroes, Beowulf is highly concerned with winning glory and carving out a legendary reputation for himself. This idea is revisited again and again in Beowulf, and the process of winning glory and fame through the performance of brave deeds becomes one of the text's most important qualities. Indeed, one could say that winning fame grants a hero a kind of immortality, as his name is remembered and venerated long after he dies.
However, there is a key difference between Beowulf and some other epic heroes, especially Achilles. While Achilles is brave and skilled in battle, he's also represented as vain and somewhat self-obsessed. Beowulf, on the other hand, while not perfect by any means, is represented as a little more selfless. He's devoted to the lords and kings who lead him, and he's concerned with bringing them honor through his own bravery. Additionally, as a king, Beowulf is represented as kind, benevolent, and concerned with the welfare of his own people. In this sense, Beowulf is perhaps more similar to Hector than he is to Achilles, as Hector is represented as a courteous family man as well as an epic hero.
Beowulf, Achilles, Hector, and Aeneas share much in common with respect to their characters as portrayed through their different stories. Beowulf, like the other characters, is bold, noble, strong, skilled as a fighter and courageous. This is seen when he competes against one of his peers in a swimming contest, knowing that it was dangerous and that he was facing a strong competitor. He also proceeds to face the monster Grendel, on behalf of Hrothgar and his warriors, and successfully kills both Grendel and his mother. This is similar to Achilles who was skilled as a fighter and who agreed to participate in the Trojan War with the knowledge that, although he will die, he will be celebrated through the ages as foretold by his mother. Hector is also a skilled fighter who is also brave enough to face the feared Achilles among other notable warriors like Ajax on behalf of his soldiers. Aeneas is also a warrior by his own right and fights alongside Hector and at some point faces Achilles.
This is a great question. As you can imagine, there are many characteristics that Beowulf and other epic heroes have in common. For example, Achilles, Aeneas, Hector, and Beowulf are all brave, proud and fearless. They are all great fighters as well who go against great odds.
What separates Beowulf though is that the epic poem views him from a diachronic lens. In other words, we get to see Beowulf as a young daring hero and an older king. In light of this point, we can say that Beowulf develops into someone who does not merely care about personal glory and honor. He is a man who cares about his people as a ruler. Achilles and the others are not kings. So, they did not have to develop this side to them.