Do armors have tiers as to what stats they can have? I see a lot of high level people running around with pristine gear and sometimes leather. Are these armors just better stat wise or are all types equal? (Chain, Mail, Leather, Plate and Pristine)
Armor types are exactly the same. A pristine helmet with +50 on each stat serves an identical use as a leather helm with +50 on each stat. Additionally there is no "better" armor type at a given level; leather armor with good stats has just as much of a chance to spawn as pristine armor with good stats.
Armor types exist for set bonuses. If you wear all the same armor type (e.g. all leather armor), you get a 25% bonus to all stats on low tier armor. The set bonus increases with higher tier armor, up to Ultimate gear at 40%.