I'm curious about the idea of a 6 ft2 pony. Under what circumstances is this a win vs. sharing air with your buddy or an emergency swimming ascent? I worry that it might not provide enough air to ascend slowly from deep dives, and on shallow dives the simplest and best option is to abort the dive by ascending immediately.
Meanwhile, the pony is one more pice of equipment to carry, along with extra hoses, regs, and gauges that will add complexity in the case of an emergency. Of course, the benefits may outweigh the hassle.
So... how do people see the advantages of a 6 ft2 pony?