A Competition Type tells Aura which offer to reprice against. Once selected, the Strategy will move your price relative to that offer. There may only be one Competition Type per Strategy.
Here is a breakdown of all Competition Types:
Lowest overall: Targets the lowest offer on the listing, regardless of fulfillment type or Buy Box status.
Lowest FBA: Targets the lowest FBA offer on the listing.
Lowest MFN: Targets the lowest MFN offer on the listing.
Lowest FBA, then MFN: First targets the lowest FBA offer on the listing. If/when no other FBA offer is found, Aura then targets the lowest MFN offer.
Only Buy Box: Targets the current Buy Box winner, regardless of price or fulfillment type.
Lowest FBA, then Buy Box: First targets the lowest FBA offer on the listing. If/when no other FBA offer is found, Aura then targets the current Buy Box winner.