Anglo-Saxon’s considered strength, bravery and battle-sense virtuous traits.
Wulfgar, who is himself “well-known to many for his might of mind, courage, and wisdom” (ch 5), is clearly impressed by Beowulf. He seems humble and honest, and he can tell by the armor that his people are warriors.
“Men from afar have come hither over the ocean's paths—people of the Geats—and the most noble of their band is named Beowulf. … By their war-gear they appear worthy warriors, and their leader, a hero who led his band hither, is surely a valiant man.” (ch 5)
Since the poem makes a point to emphasize bravery and strength, we can see that these are thing the Anglo-Saxons valued. Beowulf is considered remarkable because he can fight a monster without a sword. He is honest, because he explains that the rumors about him killing his friend when he was younger are not true. He behaves properly and humbly before the king, and that also endears him.