Two-wheeled bags tend to handle rough streets and curbs better than four-wheelers. Four wheels: The big advantage to having four wheels is mobility. You can move these pieces in any direction and wheel them along behind you, in front of you or at your side. They're also great for wheeling down a narrow airplane aisle.

The choice between two wheels (Rollaboards) and four wheels (Spinners) depends on your travel style. Four-wheel spinners are generally considered "best" for paved, flat surfaces like airport terminals and hotel lobbies because they can be pushed upright with minimal effort, reducing strain on your shoulder and wrist. They are also easier to navigate down narrow airplane aisles. However, two-wheel suitcases are superior for uneven terrain, such as cobblestone streets, thick carpets, or curbs, because the wheels are usually larger, recessed, and more durable. Two-wheelers also provide more internal packing space since the wheels don't stick out as much, and they won't roll away on an incline. If you are a frequent flyer staying in urban hotels, four wheels are the modern standard; if you are an adventurous traveler navigating old European cities, two wheels are often the more rugged, reliable choice.