We’ve been doing Eurocamp since our daughter was about 6/7, in a variety of sites in France and Italy. We have had fantastic holidays every year, and some sites were so good we went back multiple times. Some sites have tattier accommodation, so I’d recommend reading reviews.
Our favourite sites are: St Avit Loisirs in the Dordogne, Norcenni Girasole near Florence, with runner up positions for La Rive (France) and Bella Italia (Lake Garda). I would highly recommend all those sites. All have very good pools/water parks.
Advantages to Eurocamp: low deposit, easy to pay in instalments; I’ve always had a good booking experience with them; reps on site useful as a contact particularly on big sites, or if you struggle with the language.
Disadvantages: yes, you might get your holiday cheaper booking directly; we’ve found the reps can be pot luck (big sites can have young people rushed off their feet, but a small site in Italy had an absolutely wonderful middle aged couple who were like hosts).
We book our own flights and hire car, never used them for that side of things. All in all I’d really recommend them. We actually booked with a different company for our (ill-fated!) 2020 holiday, a French company called Sandaya, and I really regretted it once the covid cancellation process started. I was very envious of Eurocamp customers who seemed to get much better customer service.