Upgraded but was it actually a good deal?

Quite satisfied.

It was off-season when we went, so there was no queue. They did offer additional insurance, but it wasn't overly pushy. After giving us the keys, there was no guidance or anyone to take us to the rental car location. The car model was changed in the end and felt somewhat smaller, but my friends decided to accept it, so we didn't push further. It wasn't a very pleasant experience.

The vehicle was very new, with only a few thousand kilometers on it, and it was in excellent condition! There was a traffic accident, but we had full insurance, and the return process was very simple!

The Eurostar arrives at Paris North Station. We asked the EUROCAR staff there and were told to pick up the car at the East Station. They said it was a 5-minute walk, but it was extremely difficult to find using the map. With a large family and lots of luggage, it took us over an hour to find it. Later, we heard that many people have trouble finding the East Station rental location and often complain about it. More problems arose when we were given a Fiat instead of the Mercedes VITO we booked. Despite putting up with the brand difference, the large size of the Fiat made parking extremely difficult, as it could not fit in most underground or regular private parking garages. We tried negotiating with the EUROCAR staff to change the car, but they refused, saying there were no other cars available. As a result, we had to rely on taxis for most of our trip in France, which caused us significant inconvenience.

There was a scratch on the front of the car and it all felt a bit cavalier- I was asked to mark it on my sheet but they didn't mark it on their sheet. The man picking up the car next to mine suggested I take a photo of the damage.

NO concerns. All went smoothly.