No we decided not to. We have 1 feather on A123s and that is working out great. But we still have plenty of NiMhs for Obsidian and they work fine as well.

We are not strapped for weight either so we intend to keep using NiMh for Obsidian and SLA for Mantis and RCC2 for now. But it is good to know we can fall back to a lighter battery like the A123 if we do need more weight.