This perk works well with Martial Artist, which increases melee weapon speed and decreases weight, and Incisor, which causes melee weapons to ignore up to 75% of armor.
All ranks of Gladiator, as well as the first rank of Expert Gladiator and Master Gladiator, increase damage by +10%, while subsequent ranks only increase damage by +5%. Therefore, if interested in getting the maximum damage increase from these perks at the minimum perk point cost, all ranks of Gladiator and the first ranks of Expert and Master Gladiator should be taken before taking the later ranks of Expert and Master Gladiator.
Behind the scenes
The following is based on unverified behind the scenes information and is speculative and may not be accurate.
Vault Boy's stance, weapon, and armor is possibly a reference to the movie Gladiator, particularly Russell Crowe's character during the "Are you not entertained?" scene.
End of information based on unverified behind the scenes information.