There is one thing you only understand after ordering several times: the displayed price says almost nothing about what an order truly costs. What costs is the parcel arriving three weeks after departure, the regulator that has to be returned at your own expense, the email left unanswered when a part is missing.
The grid behind this comparator is built around that idea. Catalogue and pricing carry 45 per cent, because they determine whether the shop can meet the need at all. Shipping and support carry 35 per cent, because they determine what happens when something goes wrong. Site experience and trust make up the remaining 20 per cent.
For a French-speaking buyer in Europe, three conditions move the score more than any other. The free-shipping threshold to your own country, which ranges from 75 to 500 euros depending on the shop and on whether you order from France or Belgium. The delivery time actually met, which is not always the one advertised. And the withdrawal window, fourteen days minimum in the European Union, sometimes extended to thirty days by the shop itself.
Shops outside the European Union deserve a separate mention. Customs duties and import VAT are added to the displayed price, often on delivery, and the European right of withdrawal no longer applies. A fifteen per cent saving on a regulator disappears entirely at the first return to organise from Brussels to Florida.
One last point on public reviews. An aggregated score blends orders from every country, every product and every year. A shop can show a good average because it sells many masks without incident, while handling technical gear orders very poorly. That is why field notes from orders we placed ourselves take precedence here over the Trustpilot average.