Great little package, quick and easy to get out and pack away, nice carrying zip up pouch.
For convenience it's fine but the instructions say don't rely on its built in pressure gauge, and you really can't.
I'd say the automatic cut off is correct to within 3 or 4 psi. I found that if you set it higher than you need then it's more likely to be closer to your desired pressure. Surely they could accounted for this when they made it. Plus, if you start it up again it will put more air in for the same set pressure. I tried just running it twice for a more accurate result but after testing with an accurate gauge, two tyres were still different pressures.
It's fast, I really like the design, and its cheap, but after reading back my own review of this I'm dropping it to 3 stars from 4 (let's say it 3.5!). It'll do for a quick pump and go, but it's gonna bug me every time I use it knowing that it's not right, and if I have to check and re use it multiple times to get the correct pressures then what's the point of having it automated at all. In fact, I wish I'd forked out for a better one.