Sealey PI300
Best Buy
It was tight at the top, but the Sealey takes the win as it is the easiest to live with. It has both lighter socket and battery clamp leads, with Best Bu the former a useful metre long. The only drawback is that swapping them requires a screwdriver. The cooling fan only cuts in when needed and is quiet when it does. It coped with all of our electrical kit delivering a smooth, strong output.