Well I've never found Shell fuel to be dirty or cheap, I refilled my 2011 Audi S4 with Esso UL+ - first time that I'd used that or treated it so much for a while, that hurt my wallet more than I had expected! I tend to fill my wife's 2015 Polo 1.2TSI 110PS SEL with Costco branded fuel, but I initially did intend to fill it with Esso UL+ every 5 tank, but never quite got round to doing that, now and again it gets treated to Costco's UL+ instead.