Is fire better than arcane?
Fire is better than Arcane if you have the correct gear, just as Sweglord says. But to get that you will have to clear Ulduar a couple of times before you get the correct amount of crit to benefit from a Fire spec.
Are arcane mages good?
Arcane is really good at bursting a priority target down. Arcane can also absolutely melt any type of stacked cleave with CDs. Kit wise, arcane can shine in many areas, such as burst AoE, sustained AoE, single target and 4-5 Target cleave. Very durable caster, with 2 damage reductions, immunity, shield and Alter Time.
Is arcane good in Wotlk?
Overview. Unlike playing a Fire Mage, this spec is viable in all PvE content, both dungeons and raids. Arcane mages have a lot of burst damage but suffer if the fights go for a long duration due to how mana hungry the spec is and the lack of DoTs (Damage over Time).