Interestingly enough, this is something we started using whilst we spent time in California, Los Gatos back in 2014. I find that it is a great service. There are usually cars around that you can get ahold of within 2-5mins. Of course this depends where you are. In California this worked, and so far it’s been good for us in London. I like the app on iPhone as it’s very user friendly. This service does not exist in Denmark. Why? I don’t know and I haven’t looked it up yet as to why it’s not in Denmark. But where it exists and for us so far, it’s been good.