FlipBelt vs SPIbelt — which one should I buy?

This is the central debate in r/running threads, and there is no single winner. FlipBelt fans cite the slim profile, large capacity, and no-zipper convenience; SPIbelt fans prefer the zippered security, easier on/off, and the fact that a loaded SPIbelt can still be cinched tight. Reviewers note FlipBelt can bounce when fully loaded because you can't tighten it further.