Amazon calculates a product’s star ratings based on a machine learned model instead of a raw data average. The model takes into account factors including the age of a rating, whether the ratings are from verified purchasers, and factors that establish reviewer trustworthiness.
The USB outlets were defective. They would not fully power a small USB fan rated at .65 amp max. It would just spin at a slow speed. The fan works fine plugged into a 12VDC ciggy plug USB adapter or into an outlet on my PC. Also, the AC outlet voltage checks at only 106.9 volts. I tried for an hour to file a claim on the Bestek site with all pertinent info (order #, model #,etc.) but never was able to get through. The 'reCapcha'-type thing didn't work. UPDATE: A replacement inverter or a refund was offered. I opted for and received a full refund.
Updated: Bestek was responsive and sent a replacement unit which is working fine. So on average - it's average
Original: I brought it to go camping and use off of our car and it died sometime over it's first weekend. All we did was charge some batteries and our inflatable mattress pump. Seriously wimpy if that's all it took to kill it. I am going to contact Bestek to see about a replacement.
The entire device worked well for a very short time - then the USB ports gave out. The standard plugs still work just fine, but now I have to carry extra gear to charge devices that wouldn't have been needed if the USBs workd. It has been extremely useful when I'm out far from civilization - just a little disappointed in overall product performance.
I expected something more smaller and lighter, but this power inverter is very heavy. It looks very easy to use but is not. You have to learn how to set it up specially using the battery option. Other than that it works well.