[PDF]

The main drawback of a HS is no shield, but IMHO it only makes a real difference if you can afford one of the rare really good shields -Aegis/Barrier.
But the HS also "free" a slot with its 50% FR, so for example you can have any ID 100% FR with an Elem Armor, and an "additional" misc slot to use.
And about the high Att/Def of ID, it's true, but they often have to fight pretty good opponents, so the difference between damage 24 and 29 can really make a difference on a Prot 25 foe ...