I work as a financial planner and many of our clients use donor advised funds. You're able to gift highly appreciated investments - and get the charitable deduction (if you itemize) in the year you make the contribution to your DAF, and avoid needing to pay any capital gains tax, so the charities get the full amount eventually, rather than what's left after taxes. The 'catch' is that you can't take the money out of the donor advised fund except by putting it into 501(c)(3) organizations. So it's not a tax-saving measure in that it makes sense to do if you don't now in the future give to charities. It's strategic because you can contribute several years' worth of charitable contributions in one year to your DAF, and time it so that it's in a high-income year when the deduction is most beneficial.
I think Fidelity's offering is the best ... really low cost, easy interface (it's basically online bill-pay for charities)