The Solids % number indicates how much of the product will be left after all of the water and other ingredients evaporate during dry down. In general, higher % solids will give you more “depth of film” on the floor per coat. This means that you can get the job done with less coats of a 25% finish than an 18% finish, thus saving labor and time. On the flip side, the higher a finish is in solids %, the less tolerant of less than perfect technique during application it is (usually).
Summary: If you have experienced people putting down the finish, a 25% (like Double-Wear) will save time and labor. If they are less experienced, an 18% (like Summit) is a little easier to use but they will need more coats. The 22% product (Peak) is in the middle of the two other product in both solids % and in the way it behaves during application.