(Expert Belt is a great set though. Plays almost like Mixed Dragonite.)
Moxie has actually tested incredible for me. The attack boost with Adamant is so powerful. It lets me OHKO things like OTR Reuniclus at +2. It is also great since Dragon Claw isn't the strongest move in the world, and Earthquake can only hit Ferrothorn/Forretress for neutral. Intimidate is negligable when you are setting up on things like Gastrodon, Celebi, Tentacruel, and Toxic Politoed. Sun teams are at its mercy too. Sun teams are usually very dragon weak, especially with Sub to protect yourself from Venusaur. You do not need Intimidate to get a Sub against Sun. Did I mention how Moxie is needed for stallbreaking power without locking yourself?
The attack boost is also great when they have dual screens or if they fodder a pokemon. Mence is very unpredictable. It is already extremely good at forcing switches. There is a big difference from being +2 attack and +1 speed, and +1 attack and +1 speed. Just sub, dance up once or twice, and its literally gg if you have team support to break Skarmory/Scizor. (Use Magnezone or Heatran!)