A few years ago they were expensive to run but now most aoc work is done with Powers due to Cat t/o from Battersea etc Therefore lots more on the market and not working so much . I am not bound by these. Cat performance rules as all my flight are under private flight rules . A reasonable low hour Power will be the same price as 4 Mk 11 machines and will do pretty much the same job ( apart from higher MAUW ). The Mk11 is just as smooth and every bit as fast ..........