ActiveCapital is an SEC-approved, not-for-profit matching site, but the degree of paperwork and information disclosure makes it extremely unwieldy to use for fundraising.
I don't know if it's the best, but I personally know more people that found success on Wefunder than other platforms. Not sure that's enough of a data point to be useful though.
Convio have the most complete package, if you can afford them. But Raiser's Edge have the best name. Possibly the best name of any company in the world. It just works on so many levels.
CharityEngine is a fully-integrated cloud-computed software platform. It includes elements such as Donor CRM, Direct Mail, Payment Processing, Peer 2 Peer, and more.
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