Excellent product, and a nice gift for the kid's birthday
I bought it as a gift for my daughter. Now she is using it all the time. She has downloaded some good books for about 99 cents each. She mentioned she would never carry a thick and heavy Les Miserables with her, but with the Kindle it's a pleasure to read it while commuting. I am not sure about the battery life though, but have not heard any complaints yet. Overall, it looks like a great product. Even my wife is considering buying one for herself.
Not too noisy and holds pressure for months if left in without leakage of air. I used it only once so far, with the brad nailer, and it worked flawlessly.
The internal parts get stuck and do not start moving when the ball is pressed in for extending the ramps. A little amount of WD-40 helps a lot for better sliding of the internal part.