Rather than take a pricey taxi ride to Charles de Gaulle Airport in Paris, we booked a shared Paris Shuttle via Viator based on the good reviews we read. Cost was reasonable.
Booking was easy online. You just give the date you need the shuttle, input your flight and time and credit card info, and you're booked. You do need to be ready 4 hours before your flight time. That seems really early, but they build in extra time in case of traffic. In the end, we were thankful we had extra time at the airport because we ran into long snafus at check-in.
We were the first to be picked up, and the driver showed up a couple minutes early (it was 6 am). Despite what I read on other reviews, our driver did not not know much English so he was not communicative or friendly. We picked up two more passengers and then picked up the last passenger. She unfortunately was late, so we sat waiting in the van for several minutes for her.
Then, a couple minutes into the ride, she apologizes and says she forgot her phone at the hotel. So we had to circle back for her phone. This delayed our departure by 15-20 minutes, but that's one of the reasons they build in 4 hours for the transport.
All in all, the shuttle is a good alternative to taxis. A week earlier, we had taken a taxi from the Gare du Nord train station to our lodging. Later, we realized that the cabbie took unnecessary detours and drove past our destination so that he could run up the meter. If we visit Paris in the future, we would either do the Paris Shuttle again or Uber to/from the airport. Won't be taking any more taxis there.