I bought a Viair a few years back on a recommendation here. I've used it a few times and it's worked great.

Couple weeks back I was heading north and a guy with his son were stranded at the gas station with a very low front tire as the gas stations air was down. It was a big jacked up rig with oversized tires that needed 100 psi. It was at 30. He was hesitant to take my offer of using my little viair, as he didn't want to burn it up but I told him we'd give it a go. It took a while but we got it up to 80 psi. When we were done he cautiously touched it to see how hot it was and it was just warm.

I was pretty impressed and he said he'd be looking into getting one.

But wherever it's made, the brand is much better made than the 12v inflators you'll find at the big box box hardware stores, Walmart, auto stores, Target, etc.