I've been using it for the past 2 weeks and its exactly as advertised. The 52 quart is perfect for a family of 4 and isn't too big. I've attached a picture of it in the trunk of my BMW X1 so you can see the size.
I did some testing to see how long the battery lasts and when I set the temperature to 32F and used the plug to cool it down to 32F, the battery lasted almost 14 hours. That was inside my house which is usually at 74F, so I assume if you were outside in warm weather you would get at least 7-8 hours (estimating). Next I used the battery ONLY to cool it down to 32F and left it running on battery only and it lasted about 8 hrs. I didn't test out the freezer mode on battery only as I'm using it to keep my drinks cold right now.
The cooler itself is quiet, even with the compressor running, I didn't have any problems with the noise.
The only reason why I"m giving this 4 stars instead of 5 stars is that when I got it and set it at 32F, I noticed that it didn't feel like 32F. I had a extra thermometer so I put it in the cooler and it was reading 38F instead of 32F. I emailed the company and they showed me how to adjust the temp to match the inside and outside. It was easy but from the factory, it should be set exactly to match. One last thing is the cooler temperature ranges from the bottom to the top. When its set at 32F, the bottom is reading 32F but the top is reading 38F. Still within acceptable range for a fridge but it should be noted that there is a difference.
Overall I'm very happy with the purchase and would definitely recommend it to anyone looking for the convenience of a battery operated cooler.