Originally Posted by Maven

Depends on the candidate.
Candidates who have good writing skills should go for MOD test because two papers of it are based upon writing.

Besides, candidates who want to remain social, dont want to remain socially reserve or bound should go for FIA, irrespective of how their writing skills are.

MoD job is for National security organization which somehow prohibits ambit of social circle of its employee for the sake of secrecy.

Like NAB, FIA is powerful organization too. Since its a civilian organization, therefore no such restrictions.