They are all horrible and I doubt this model is going to work unless all the startups there are already profiting.
Having 100% of a business that makes $0, "but have the potential" isn't worth shit.
If you're a developer, then you know what sort of ridiculous proposals are common.
"Build my facebook clone for absolutely zero pay, but I'm feeling gracious so you get 15%!"
I do, however, like the idea of working on granular bits of startups and distributing my risk in a way that makes me more likely to have something take-off than committing to a single startup but not necessarily having any more control than the 'freelancer' mode.