It's not been out long with Millers. There are only two oil companies in the world who are using this technology. Millers have used it in their gearbox oils for a few years now and have only just moved it to their engine oils.
Search 'fullerene' in google to learn about the molecule and why its so good. It acts like a ball bearing reducing friction and being carbon its a tad strong.
Obviously there are loads of 5w40 oils available, but this is the best.