The SA doesn't appear to have Bible verses on it. I would guess that those add to the overall cost of the Crusader without adding quailty to it. Some just like the way it looks because of those additions.
For most of our normal applications, I'm sure that they are both very competitive and of similar quailty and durability.
The saint is a basic ar with a freefloat handguard. The crusader has a good bit of add on parts. The crusader has a 14.5" barrel with pinned dynacom, so no changing parts with a major hassle. For the price of the spikes I'd buy a bcm.