Mounts
We'll start with the Equip Power which for me is the Legacy (or legendary) Snail's quick action +25% AP gain whenever we cast a daily is simply amazing. That means our debuffs have higher uptime, (I can cast a daily right as Combustive ends, about every 10 sec more or less) which makes the dps do way more dmg. The price though can be a negative factor in which case you can get the 15% AP gain mounts as they will do equally well if you don't mind a small gap in between.
As combat power I selected the Module 14 Bat Swarm for the obvious 5% damage buff and 5% debuff but also for the unique looks.
As for mount bonuses I picked the following: Shepherd's Devotion and Artificer's Persuasion because we can cast our daily and artifact so fast that the team can stay buffed from us most of the time. Gladiators Guile for movement speed because being left behind isn't helping the team much, especially in dungeons like SP and Tomb of the 9 Gods. Protector's Camaraderie because extra power and defense to stay alive, never hurts. For the last mount bonus, I tested for 3 months now and selected the Combatant's Maneuver. Since I use Ray of frost, or Chill strike the extra combat advantage is better than most other bonuses.
For Insignia you can use Aggression to cap your armor penetration, Mastery for recovery, Dominance for power and Leaching for lifesteal in any combo that suites your stats and needs. Of course you can use any mount that procs the specific bonus you need.
