Walmart carries a nice little 3 gallon "hot dog" type compressor made by Campbell Hausfeld. It's only $75.00, and is a plug in type, not a 12 volt. I work at Lowe's, and sell Campbell Hausfeld, but for some reason can't get this particular model. I have seen them in Walmart, and it's a nice little unit, and I'll probably pick one up for my Lexi. It's also a bit more compact than the round pancake your looking at.
I do carry a 12 volt compressor in each of my vehicles for emergencie's, and for a car tire their OK. Tried one on my Class C tire and it pooped out, not getting anywhere near 75-80 psi. I know there are quality 12 volt compressor's out there, but if you have a generator and can run a regular compressor, why not?
Grumpy
Just for the heck of it I checked Amazon and they have it for $69.00. no tax, and free shipping.