I'm sure they just buy what they can find and sell it to the public. This is where good service after the sale is monumental. These guys don't seem to be shining in that area. I'm with
captndave737. I'd get another and put 5v to it to see if you can keep it from letting out the magic smoke. It appears that smoke you let out was like an alcohol fire. Not visible by the naked eye.
Not endorsing these but I bet they are that far from what everyone is selling. And Ive found them to work good if you dont direct mount them to the rail. It seems they dont like vibration so I got a -3 braided hose and remote mounted it.
Those are the same sensors I got off Amazon. They leaked. Especially if you're running E85. They'd last about a week.
I also used one for oil pressure and had terrifyingly low oil pressure readings that descended linearly with temperature. I was about the pull the motor when I tried an SSI from Caspers and bam - oil pressure was fine. Those sensors change readings when they get hot. I never cut one open, but I suspect the transducer is exposed directly to the working fluid on those. Better sensors protect the electronics with a stainless membrane.
I suppose if you can remote mount them to keep the vibration and heat away, they might last. Maybe. Everybody's mileage varies. Mine wasn't good. If you can remote mount them above the rail, there will be a pocket of air trapped against the transducer. Fuel won't ever touch it.
The SSI I got from Casper got plugged into the exact same wiring (5v power feed) and worked, so I'm with
@shmed, I think the instructions might be wrong. SSI has two versions of the sensor. a +5v and a +12v. The +12v version actually works from +8v to +30v. But the +5v version doesn't work past ~7.5. BUT, the SSI Caspers sells have overvoltage protection. Feed it 12v and you'll get no reading off the signal wire, but you won't smoke the sensor like you do with the cheapies. Rewire it for +5v and it'll keep working.
If you get the sensor from Casper, the SSI sticker will still be on it. You can match the part number up on Amphenol's (they own SSI now) website and get the actual data sheet for the part.
I don't know about any other brands. Not knocking anybody's, just relating what I've dealt with.