Good post by Geoff Livingston on Only One Kind of Branding Matters:
Only one kind of branding matters, and that's the customer experience.... You can manufacture as much messaging as you want, but if your brand promise doesn't meet the customer experience then your efforts will fail. Fast.
That's why so much nonprofit branding is such a dismal failure. It doesn't (or can't) do the real job of being the donor's experience. It's just a bunch of wishful thinking in the from of design and copy guidelines.
If the donor's experience with the organization isn't what it should be, the outward appearance doesn't make any difference. In fact, advertising wisdom is that excellent advertising only accelerates the demise of a bad product.
If you not an organization whose beneficiaries and donors are the same people (such as an arts organization, a hospital, house of worship, etc.) the best and almost only thing you can do to make donor experience great is have a thrilling call-to-action and amazing reporting back that keeps proving to donors that their giving does what you say it does. That and flawless service.
That's the branding that makes a difference.