Got this baby for Christmas. Unfortunately, I had to use it.
First the details. This unit has an LED flashlight, air compressor with gauge, and 500 "instant" AMPS of jumping power and 1000 "peak" amperage. It also permits USB charging in a pinch, simply flip on the USB button to charge your phone in an emergency.
First for the good: It can jump a very dead SUV's motor.
My Explorer was dead last weekend, so on two occasions I jumped it back to life with this unit. Hooking it up is easy. Remove the clamps, tie the red to (+) and black to chassis ground. There is just enough cord for you to reach your battery, which winds up and around in an "8" form on each side of the unit. Turn on the master switch, and hope you don't have reverse polarity--if you do, the unit will beep and not attempt to jump the vehicle. (I didn't test this feature, but I presume it works.)
I flipped the switch, waited a few seconds, and hoped for the best. While the Explorer didn't crank with vigor, it did crank with enough confidence for me to know it could start.
So, the car started. Can I really ask for more?
As a bonus, it has ports for USB charging.
The bad: Chemistry.
The unit does not include a charging cord--you must run a household extension cord to the unit to charge it. This is not a huge deal, but a wind up AC cord would have been nice to have. You can also charge it with DC power with an optional, not-included adapter, but the device can be overcharged in this manner (not so when on AC.)
The air compressor is noisy, and one would think that you would have the mandate to recharge the unit after each use of the compressor to preserve charging power. The unit itself, regardless of use, should be topped off every 30 days at a minimum. I've found it to take over an hour to charge using this calculus.
Further, the unit can't stay put in the back of the Explorer. It's so heavy that it moves around everywhere with impunity.
Overall: Does what it promises, and throws in the bonus of USB charging and a flashlight (which I forgot to use when I was jumping this thing in the dark, of course) along with air compressor. Problems include the charging inconvenience and it doesn't seem to stay put when stored away.