I tried the USB one, too. Took forever to get Google to even accept my password to get the app, and once I got it set up I found the image resolution too low to do me much good. I'd hoped it would be usable at work.
Tossed it and went back to my Harbor Freight older model. It's a lot bulkier, but at least I can get a good image, and I can save stills or a movie to SD disk or connect directly to the laptop for a bigger picture.
IF you want to go expensive, Snap On makes a real beauty for around $300, but no video or save function if I recall.