If you already have a Prius, the set-up described in the article is a neat last minute "MacGyver," but I don't see it as a substitute for more substantial preps. That car is a pretty expensive piece of equipment.

We put in a natural gas 8KW gewnerator, fully installed, for about 5K, and it provides a lot more power than the Prius set-up.

Portable gas generators in the 2 - 5 KW range are much cheaper. My old 5KW ran 12-14 hours on 5 gallons of gas. Prius or generator, you still need gas.

So IMO, the Prius power station does seem to be worthwhile as a primary source of emergency power. But first, get a real generator. Then, if you have a Prius and want a backup option, an inverter seems like a reasonable idea.

As always, the first thing to do is to calculate the critical amount of power you cannot live without, and size your preparations to at least cover this requirement. Then, if you can, add some power to cover other needs.