I bought some Kojak's for barakta's Sprint to see if faster tyres would make it a bit less hard work compared to the boring sensible Marathon Pluses. They certainly did - rolls almost as well as my bikes do with Marathons, with the bonus effect of cornering like it's on rails.
Obviously they're slick, so rubbish off-road, and while they've managed to avoid the fairy, I suspect that's mostly due to luck and lack of miles. They are delightfully cheap, though.