The peaking profile will probably be different, so unless you have a very adjustable charger, these will definitely require a new one. I don't see that as a big deal though. Chargers wear out and fail after a while anyway. If there is truly a performance benefit to be gained, the RC community as a whole will embrace the change and the support products we need will show up. If not, they won't. I remember a few years ago lots of people saying that A123/LiFe batteries were going to be a big paradigm shift with their massive amp capabilities. But it turned out that better power to weight ratios could be had with Lipos as they quickly developed, so LiFe batteries pretty much were relegated to high performance receiver packs and a few niche uses. I hope these work like many of us are hoping, but if they don't we'll know soon enough and the hobby will probably just continue to develop better Lipos.