I didn't know Halio was London based I swear by Uber in Toronto and will use it in London when I'm there next. A long time ago (year and half?) I looked up what the difference between the two was and it wasn't much. Comparing apples to apples, namely, plain old taxi service, they aren't much different but Uber is straight no minimums, gratuity set to a standard rate. I decided not try Halio at the time and stick with the Uber I'd been supporting (arbitrary I know) and enjoy not having to worry about any settings or anything. Hail cab, hop in, hop out, done.

On the business side I think Halio is an actual cab dispatcher company, whereas Uber is just an app service that any cabbie can use..... Anyways, yeah, have nothing but good things to say about Uber and kind of laugh at the mess going on in London right now