Both techniques are very effective ways to fundraise. The one you choose will largely depend on the resources available to your non-profit organisation.
Crowdfunding is often a simpler approach than peer-to-peer fundraising because you only need one donation webpage. This one donation page is shared online by supporters, and all donors are directed back to your donation page. However, the key to crowdfunding is promoting your page amongst your donors and followers.
Peer-to-peer fundraising is slightly more complex and requires some time and planning. Your supporters will be creating their own donation pages, which are linked to yours. Their pages can be customized according to their preferences, but you will still receive all funds raised. Since it will be your supporters who will be raising the money, you may want to provide some input if necessary.
Peer-to-peer fundraising is exponential, as all individual campaigns of your supporters have a ripple effect and will bring you more donors. It can potentially bring you more visibility and raise more money than a crowdfunding campaign. Peer-to-peer campaigns may require more planning, execution, and direct involvement of the participants than crowdfunding campaigns. Nevertheless, the result can truly be amazing!