The juries out, but I think Godzils design is the winner despite its complexity. Although it will only present the same regulation as a battery, we have to remember that BATTERIES are NOT POWER SUPPLIES!. All your fancy shmancy designs are in fact TINY POWER SUPPLIES and behave like POWER SUPPLIES, NOT BATTERIES. Godzils will act just like a real battery - even down to emulating the internal resistance. Also it's efficiency looks to be a bees dick as good as 100% as is possible.
However, it is not a completed design and no physical prototype exists yet. I think Godzil needs a Kickstarter in order to pay for tooling costs, materials, coke & hookers, Ferrari, etc.