THF AF -> head, body, hands, legs are all great. Head is outclassed by some other pieces and body loses to relic +1, but both are worth having if you need acc
THF Relic -> body, hands and feet are all great for different reasons. body is BiS for anything WS related.
BLM AF/Relic -> pretty much all out classed by easily obtainable Hagondes gear. AF feet are decent if you need matk and don't have access to Umbani or don't want to throw money at Hagondes. AF body is nice if you don't have seidir (sp?) for the 2% damage -> MP conversion. AF legs and Relic hands are decent dark magic pieces. Everything else is pretty meh.
WHM AF -> Legs are awesome for cursna set. Hands are a good healing skill item if you cap healing potency in other slots.
WHM Relic -> Legs are an absolute must. Enhancing, barspell, and shellra bonus. All around awesome piece. Feet are decent and have cure potency on them. Body is good if you ever use regen.
Can't speak to the others