I have owned both a STING and also now own the high wing SIRIUS. I changed merely because, prior to a knee replacement operation,  an arthritic knee gave me difficulty getting in and out of the Sting which can be viewed more like a sports car. The Sirius however, being high wing with gull type doors is very easy for the less agile to get in and out of. Both offer excellent visibility and performance. The Sirius has the further advantage of a larger baggage area ideal for touring. (We managed to fit two Brompton folding bikes in!)