One competing design is the Speedlifter http://www.rosebikes.co.uk/article/speedlifter-t-100

Yours looks better in operation and I presume doesn't require so engineering skills or a specialised tool and the services of a bike mechanic to install? As to looks I'd be changing the design for aesthetics, the gas struts look cool but the centre bracket is too chunky, makes everything look too heavy; a thin framework like a Moulton bike's space age frame or like clip on aero bars would look better.