A Magic Critical is +10 MAB, but you only get it 10% of the time (hit rate +10). That averages out to be +1 MAB per cast. Nice for epeen numbers, but a hat with +4 INT and +2 MAB should out parse a hat like the one pictured here, statistically speaking. Of course, the rules change if you're able to increase the rate at which it procs.
Yes, Xanathos, Yigit Turban *does* have +2 MAB. It does not have +INT to go with it.
For some this could replace the Wizard's petasos. By switching to this you lose 1 DEF, 5 MP, and 10 to thunder. BUT, you gain conserve MP +3, MAC +2, MCHR +10. It all comes down to whether or not you want to spend 10$ for the change.