Oh, snap! Leave it to the marine equipment industry to put up some competitive fight! Here's a new entrant to the market that I hadn't seen before.
Midland's PPG100 Portable Power Station. Looks competitive. Submersible when stowed. 950 Watt-hour Lith-Ion onboard. 25 lbs. And unlike inergy, these guys have established distribution channels, so this sucker's available at places like REI and Frye's. They hit a price point that's $300 lower than the comparative goal zero product.