Joomla Donation was the first product we found that gave us this flexibility to have multiple price levels, and the "Go For The Gold" text box to let them name their own donation amount in the front end without having to do some over-ride on the paypal side.
So we started with a good product fit!
Take note that Joomla Donation is CB integrated. Not only does it show payment history on CB profile, (an interesting convenience), but it means your users don't have to re-register which was critical to our user experience. The module will auto-populate the user information into the transaction form form CB!
So the real surprise was that here I am at 11pm in Hawaii, I submitted a pre-sales question and got an instant response, answer not auto-responder. Ran into a couple of snags on install (note that the plugin is a CB plugin not a Joomla plugin) that will save you some questions...
Couldn't find any online documentation, but the company made up for that with instant tech support. Did a goto meeting and was able to troubleshoot a couple of issues and even addressed some formatting issues associated with our template.
I highly recommend this as a new entrant to the space. Expect more raving reviews to come as more people purchase this module!