I upgraded from the JNC660, which was a great unit. (Broke mine by accident, no fault of the unit.)Decided to upgrade to the 770R, mainly for the longer and better cables. I like that there's an off switch so the cables aren't always live. It's got a built in light that's fairly bright, but I can't imagine using it often. Adding the USB ports for charging was a nice touch.Yes, it's heavy, but this is a real jump pack, unlike many of the Lithium Ion packs you see out there today.
Rating: [5 of 5 Stars!]