Once upon a time, I ran an open source project that accepted both donations and paid subscriptions, with similar benefits offered for both (larger quotas on the hosted service). A small amount of donations trickled in from time to time, usually from individuals. But most companies, both corporations and sole proprietors, chose the paid subscription. Even at a higher cost. After a while, I scrapped the donation option entirely. I own a business, not a charity, after all.

Lesson: Unless you're registered as a 501(c), or an organization with similar status in your jurisdiction, don't even think of accepting "donations" from anyone who retains an accountant. It just doesn't work that way, open source or not.