Use public transportation or use pre-arranged transfer to hotel in Paris?

Ordinarily, I might be tempted to save a few bucks and take public transport. OTOH, you are coming a long way. You're going to be pretty tired. €70 isn't awful. Is that €70 for both of you, or per head? If it's for both of you, I'd go for that in a heartbeat.

You're probably going to have to kill some time before you can access your room (though it's worth asking for an early check-in, it often works out, even if only an hour or two early). You'll want to kill that time doing something outdoors, in the fresh air, something that helps you enjoy being in Paris, even if that's just walking -- rather than slogging through the metro with your bags. After all those hours in transit, it's worth lightening your load a bit IMHO.

In life, most of us set priorities in terms of how we spend our budget. Same with travel. I usually use moderately priced inns/hotels and use public transportation, because I'd rather spend my money on other things. Usually, when I arrive to Europe, I'm pretty excited and raring to go! In Paris, I've always used RER B from the airport, and actually, I don't think I've taken a taxi or similar from any airport in Europe. But, other people make different choices based on their energy level and budget. I actually enjoy walking a few blocks to get to the hotel, as well.

There have been times that we've considered a taxi when we have time constraints, but in general, I think the RER gets you to city center just as fast if not faster than a taxi.

I really think its just a personal decision.

Navigating the RER and then Metro while jet lagged and carrying bags isn't much fun. But 70€ seems a bit much, since it's a flat fee of 58€ to places on the left bank when taking a taxi from the official taxi queue at the airport. https://www.parisaeroport.fr/en/passengers/access/paris-charles-de-gaulle/taxi

Even if you can't check in until 3, most hotels will store your luggage until your room is ready. Dump your bags and head out for some exploring and a nice lunch.

Arriving from SFO in the morning, I always take the RER from CDG to Paris and since the RER goes to Gare du Nord, where my hotel is, it's all very convenient and direct. In your case as your hotel is near the Eiffel Tower, you'll have to take the Metro at Gare du Nord if you choose the RER. I did that once when the hotel then was near the Eiffel Tower, ie, went public transport all the way.

I suggest taking up the hotel's offer, take the transfer service. True, not until 3 pm can you check in but you may be able to drop off the luggage prior to to that. My hotel allows that, say I show up at noon. The hotel allows me to check in if the reserved room was not used the night before. Otherwise, it certainly allows the luggage to be dropped off.

I say spend the money on the private car. You have 2 potential flight or airport delays and if you end up at the airport in a long line, you might kick yourself for not spending the money and having the ease and comfort of a smooth ride from the airport. I did the Best of Paris solo in 2018. I had prearranged for a car from my travel agent in Canada, and it was worth every penny. The hotel stored my luggage and I was free to walk around sans luggage to get my bearings in the hood and have a nice light lunch. I was at a RS hotel near the Eiffel Tower as well. The only other suggestion I would give would be to get a business card from the hotel. I get turned around easily and combining that with jet lag, all the beautiful buildings look the same. I asked a few Parisiennes for directions and easily returned to the hotel. I didn’t have a smart phone at the time, so couldn’t google map it.
You will absolutely love the tour.

The best travel "splurges" I've ever done after flying all night have been taking taxis from the airport or the train station to my hotel. , Money well spent spent, IMO.

In Paris, I might take the RER B to Gare du Nord, but unless my hotel was very close by, I would take a taxi from the train station to my hotel. It's the last mile that will kill you.

I'd take a taxi -- but when I was young and could easily carry bags up and down stairs, I took the train. Either is fine if you can manage luggage easy on stairs.

The official taxi queue is always there when you get there, quick and cheaper than 70 Euro. And there will be no issue of finding the driver or having issues due to a late plane. I think hiring a private driver adds complexity rather than reducing it. (heard too many stories of 'we were there and you weren't' and then not refunding the cost etc.

I don't see any reason to pay 70€ for a "vetted" transfer service when taxis are readily available for 58€. If you had a special issue like you needed a car seat, for example, the 70€ would make sense. I have taken taxis, the RER, buses, and transfer services from CDG to Paris and all of them have their place in my travel plans and budget but I have never had a transfer service car that did not require a walk from the terminal as opposed to taxis which are right outside.

Orlando to Montreal to Paris -- whew! That's a lot of flying. I don't see the advantage of the 70-euro option. I'd go with the regular taxi for 58 euros. Go to the official taxi stand at the terminal, ignore the scamsters inside offering rides. Or, cheaper but less convenient, the RER B to Gare do Nord or St-Michel and then a taxi to the hotel. Have the hotel address on a piece of paper to show the driver if necessary.

Surely the hotel will accept your bags whenever you arrive, even if it's too early to check in. No point schlepping them any farther than necessary. Then go out and start turning your clocks to Parisienne time, maybe with some caffeine and lunch to fortify you!

Ok, y'all have convinced me to take a taxi or the transfer service from CDG to the hotel versus take the RER, walk a bit, take a bus, and then walk a bit to the hotel. Hubby and I were reminiscing about the city bus we took in Lisbon, Portugal at about 6 am on a Sunday morning to get from the airport to our hotel. We speak no Portuguese and no one out at that time of the morning spoke English. We managed to communicate our destination to an elderly gentleman who stayed on the bus past his stop to make sure we got off at the correct stop. But that was 23 years ago!!! We could manage stairs and trains and buses but getting rid of our luggage and then exploring unencumbered sounds like a better choice, especially if it is raining.

@Dick
Yes, we will do an airport taxi. I started looking at the wait time charges for the pre-arranged car and that was a no-go. I am not going to be stressing about a transfer if we get delayed! It was going to be 77 euros when I started going through the booking process to see what was what.

Do taxis take credit cards? Do I tip over and above the flat fee of 58 euros?

The taxis are supposed to take credit cards, I would recommend asking before you get in. We took one a couple of trips ago and one man kept telling passengers he didn’t take credit cards. Finally after four families took other taxis he told the French woman in front of me he just realized his machine was working She told him off in French and got in the car behind him. He tried
the same trick with me in English and I just looked at him and said “oh I wouldn’t want to put you out” and got in the car behind him. I’m sure he eventually got a passenger but it served him right to get stuck for a while

As for tips, I think we probably gave him €60 at most. The cab driver was nice and helpful with our luggage so he got a few euros (At the time I flat fare was €55)