Exactly what power did the Ring of Fire give to Gandalf?

[Knight of Gondor]

I believe that it enhanced his physical capabilities (the instances already mentioned by many, such as the fire used to fight the Nazgul or wolves, but also the "bright flash" and smell of gunpowder when the Goblins were attacking in The Hobbit), but its greater power was in kindling the hearts of men. Hence, inspiring the hope that he did during the siege of Gondor. But I believe its greatest potency was displayed in events such as the healing ("kindling") of Theoden to go to war, or even inspiring an otherwise uncourageous hobbit to run out his door and join a band of dwarves to Erebor.

Let us not also forget that it gave Gandalf insight into the minds of Galadriel and Elrond, the other bearers of the rings.

I thought that Appendix B stated more about the rings, so I shall go and read it tonight.