I bought something very similar to what you're looking at, but got the twin piston model.
To be honest, I though it'd be rubbish, especially for the price, but it's been excellent. I pumped up one of my SIII Land Rover tyres from nothing in about 2 mins. I've used it on loads of mobile trailer services and it's been great. I also used it to do the motorbike tyres too, straight from the bikes' battery. The vehicle has to be running though, because I think it draws about 30amps when on full chat!
It went from this psi:
to this psi:
in this amount of time:
it look like this:
And I bought it from Amazon for £59.99 - and free P&P too
I'm in Fareham too - if you wanted to have a play, before you buy one, feel free to drop me a pm.