I don't understand the enthusiasm for Open Collective, they are a for-profit, VC-backed, private company that take 10% of your money (+ 2.9% + 0.30c fee from stripe).
https://liberapay.com/ (specifically the "Teams" bit), seems like a great alternative to this - and fees can be as low as 0.6% / €0.59.
Liberapay is just missing the startup-style hubris :/ (and the sexy website)