Would you prefer a bigger cut, or more dollars in your pocket? That isn't a very hard question for most people, but they act like it is.
For example, assuming your average donation is somewhere in the region of $10, you're paying somewhere in the 6 ~ 8% region to Paypal. Yeah, annoying. But if you cut your costs of payment processing in half, that only increases your net income by something like 3.1%.
There are much, muuuuuuch easier ways to get a 3.1% increase, particularly if (like most folks who accept donations) you have never attempted to optimize anything about your business. For example, most folks I know who accept donations are afraid of appearing commercially motivated so they create a discrete donation button and then place it down a rabbit hole in a mythical kingdom surrounded by lakes of fire and cloaked with Grumble's Greater Enchantment Of Decreasing Conversion.
Instead, move it to above the fold on your page, increase the size of the button, and prominently (and without sounding ashamed of yourself) ask for the donation around places where you provide value to your users (which is when they are the most inclined to say yes, because they're feeling all warm and fuzzy about you).