The way that the logs are oriented in the firebox can have a big effect on how they burn and on how much heat the stove can put out over an extended burn.
A stove with a firebox that is deeper than it is wide has more heating capacity, since its full volume can be used. There’s also no danger of logs falling against the glass door (if there is one). This orientation usually provides better combustion as well, since more air can be drawn over the length of, and between, the logs.
A stove with a firebox that is wider than it is deep has less heating capacity, since only about 50% of its firebox volume can be used. If it’s loaded too full, logs can fall against the glass door, preventing further stoking and/or creating a hazard since the live coals can easily tumble out.