What are the mechanical differences between Blazons of Shared Power and Doubling Rings?

Question

Doubling Rings came out in the CRB. They make dual-wielding cheaper, the fundamental runes of one of your weapons are duplicated to the weapon held in the other hand.

Blazons of Shared Power seem to do the same thing, in a slightly different way.

The differences seem to be in fluff. You do not have a limit on how many rings you can wear, so replacing the two rings with brass emblems is meaningless mechanically.

Both work with one-handed weapons wielded simultaneously, neither works with thrown weapons.

So why would I pick one over the other?

Answer 1

The weapons used with Doubling Rings can be swapped freely.

SpearCarrier No. 2’s answer clearly addresses the main advantage for the Blazons - they work with ranged weapons and can be attached to dual pistols.

But the downside of the Blazons of Shared Power is that they are themselves attached to a specific pair of weapons. This means that you cannot, for example, drop your offhand weapon, and draw a different one in combat, while still benefitting from the Blazons.

By contrast, the Doubling Rings merely duplicate any qualifying weapon you hold in one hand to any qualifying weapon held in the other hand. This allows for the offhand weapon to be swapped to one with a different damage type or other property mid combat, or use by a player with the Weapon Improviser archetype, for example. It also means that, with Greater Doubling Rings, you could have two different sets of property runes on two different weapons, and choose which “loadout” to apply to both weapons, based simply on which hand is holding which weapon. Blazons of Shared Power simply don’t offer this versatility.

Answer 2

Blazons of Shared Power work on ranged weapons too

Doubling Rings work only on melee weapons.
Blazons of Shared Power came out in Guns and Gears, the same as firearms. Now you can dual wield pistols on a budget too.