[Kaiser]

My friend told me if i wanted to be a really good mage i should find out where to get this set of armor. What is it and is it worth getting?

[Taskmage]

It's a set of armor that's bought with points from assault missions. You can see the stats here: http://wiki.ffxiclopedia.org/wiki/Yigit_Gomlek_Set

I'd get the whole set eventually for black mage or white mage. It's very hard to beat the bonus to mp restoration with any other equipment combination, and the magic attack bonus and intelligence stats make most of the pieces good nuking gear.

[Feenicks]

For BLM there is better nuking gear available, but for any mage job that can equip it, there's no better set as far as healing MP goes. You'll want to get the whole set so you can still have Auto-Refresh up when maximising your hMP.

[Callisto]

Aside from a healing MP set I wouldn't use this for most applications as a mage because there's better, easier-to-obtain alternatives for most jobs, but as they said above it's nice to get the full set for resting.

The Gomlek itself however, is very nice for Bard, especially in merit parties, the song spellcasting time- is only available on one other body piece, the Sha'ir Manteel, which is pretty freaking expensive/difficult to obtain.