I don't! As mentioned in another comment, I had not heard of them before. I'll be trying them out.
On first blush, it looks fairly close to what's in my head - so perhaps this is not a thing to chase.
The one critical difference I can spot early on is that their system appears to be closed-source. Were I to do it, it would for sure be open. I want to see a method of supporting yourself with code far more than I want to make money myself. For example, in this moment, I like what they're doing and would love to contribute to the work myself to empower the goal of having more indie software devs in the world, but I would have to quit job (not happening), apply (might not get hired), and then work on whatever features are in the business' best interests (which won't necessarily be in the user's best interests).
All that said, they did it already and I didn't, so hats off to them. I hope bountysource gains more traction in the future.
Edit: another reason to have <bountysource-clone> be open source, is to recurse the value add. The site would develop in the same way any open source project does (if / when they get popular): by people implementing what they consider the most critical features.
Bounty source requires you to finish the work before you get paid, how are you supposed to assemble a development team around that? Prefunding is still unsolved.
Edit: Take an existing opensource crowdfunding platform and try to make it suitable for crowdfunding opensource projects, perhaps the first campaign could be for goteo itself?
The tech mogul who denies luck exists and contributes all of their success to their own ingenuity and prowess is a straw man. Perhaps with a few notable exceptions, that person simply does not exist.
Everyone knows luck exists, and almost everyone acknowledges it plays a key role in one's success.