One level living will retain better value and appeal to a larger audience. The one story has a larger footprint, but minimal stairs. The older generation will always be looking for this style of home.
Neither style is automatically better. Ranch homes often appeal to a wider buyer pool because they are easier for aging buyers or people with mobility concerns. Two-story homes may offer more space for the price and are popular with families. The best resale potential depends on the neighborhood and local buyer demand.
If you are hoping to buy a house, you likely have a budget in mind. Hopefully, that budget includes fees that come with the process, not just the purchase price. The good news for buyers is that they aren't directly responsible for paying their agent. Agent fees usually fall on the seller.