Used Uber over the weekend going from Latin Qtr/Rue Monge area to CDG T1. 50EUR in minimal traffic.

Family used a prebooked G7 cab a couple of hours later which was slightly cheaper 49.xx EUR. So appears Uber has no savings over taxi in this instance.

Additionally, Uber did not use my available USD credit balance but instead, charged entire fare to credit card. I've emailed them to see why.