In the lab, we weighed each piece of luggage for comparison purposes. We looked at the number of compartments and assessed the practicalities of packing and unpacking them.

We examined every zip, buckle, wheel, and handle in order to identify features that might make your life easier, as well as those which might complicate your travels.

Every carry on we tested offered great capacity, but a few were easier to organize than others. We packed our Best of the Best with clothing for various kinds of trips, and had no issue fitting everything we could foresee a traveler needing. 

Keep in mind, while it's nice to be able to fit everything you want in your suitcase, there are weight restrictions imposed by airlines which you need to know about when you’re packing. A handy luggage scale could be a wise investment. 

After a thorough in-house inspection, we also took the suitcases onto the street to test their maneuverability and durabilty.

Each bag passed through an assault course of steep gradients, cobblestones, curbs, and tracks.

We wanted to see how well each bag would fare during its obstacle course and if there were any areas of strength or weakness we should know about.

To avoid any chance of bias, we brought some experts in the mix.

First, we consulted travel professionals to find out what they look for in carry on luggage.

Next, we talked to people who already own the carry on brands in question.

See our Professionals Weigh In and Consumers Weigh In sections for more info.

It would be nice to think that every piece of carry on luggage complies with every airline’s criteria. Sadly, there’s no guarantee of that. The frames used to determine whether a bag fits an airline’s overhead bins vary from one terminal the next.

One of the first things we did was ensure that our picks would fit the most stringent of airline requirements. We strongly suggest that you do the same before buying new luggage. Additional charges for checking oversize bags can be exorbitant!

Two wheels or four? The answer to that question depends on your preference. Four-wheel spinners and simple two-wheel cases are two of the most common structures you’ll find on today’s market.

Each type offers its own pros and cons.

Two-wheel carry ons cannot be pushed; they must be pulled. Furthermore, they have a tendency to capsize. This is especially true of cases that are unevenly loaded.

Some travelers are tempted to cram items into their case, but an unbalanced two-wheel bag is a nuisance to pull for any distance. It won’t stand upright, and it may pull left-right or twist uncomfortably in your hand.

That being said, some consumers believe they can get more packing space out of a two-wheeler.

Of course, that depends on the overall dimensions and structure of the case. Spinner wheels may also be more vulnerable to damage than the inset wheels you find on many two-wheel cases.

You would think that a four-wheel spinner carry on suitcase would be ideal. A set of four wheels certainly lends stability, and spinners are found on almost all hard-shell luggage and some soft-shell pieces, too. But there are a few things to keep in mind.

Put a four-wheel spinner on a hill, and it has a habit of wandering off! And frustratingly, none of the bags we tested offered a way to lock the wheels. Additionally, hard cases tend the scratch more easily.

But despite these concerns, the hard case carry ons fared well in our other tests. They rolled well over stairs and curbs, and did not tip over once.

We also liked being able to spin it, especially when trying to get through crowds or around obstacles. The wheels on our top picks easily corrected themselves whenever we changed direction or reversed.

Our testers were by no means gentle, but no axles snapped and no wheels broke during our outdoor portion.

In fact, every carry on coped extremely well with the physical demands of our route We think that’s admirable, as each carry on in our test rig traveled over cement and cobblestone areas, and climbed 20 curbs.

Back in the lab, we checked handle anchor points, examined zippers and closures, strained the straps, and generally gave each item a good workout.

Despite a few scuffs and scratches endured on our trial run, all items remained sturdy and intact.

If you search for owner feedback online, you'll undoubtedly find complaints about wheel/handle breakage, stitch unraveling, and zipper failure. However, we experienced no such problems during our test run. Product quality was stellar across the board.

Notably, most of our testers preferred the four-wheel spinners on a flat surface due to the flexible movement they provided.

Charlie Leeper is a baggage handler at Dallas Airport. He deals with more suitcases in a day than most of us do in a lifetime. As a frequent flyer, Charlie prefers a soft bag. "The number one rule is to avoid checking your bag. I can cinch a rucksack down to fit just about any bin." He recommends buying a carry on with as few zippers as possible. "If you do have to check your bag, they [zippers] get caught and ripped off all the time."

Jessica Dinn is a flight attendant who travels two to four days a week. She uses a basic, two-wheel carry on with one main compartment and a couple of external pockets in its soft shell. "If packed strategically, I can fit two to three pairs of shoes and five to seven outfits — at least seven days of clothing." Jessica admits that she might buy a bag with spinner wheels some day, as her current bag does have a habit of capsizing.

Todd Liss is a brand manager who flies two or three times a month. He only ever takes a carry on, in which he typically packs three to four days’ worth of clothing. He's another fan of soft-shell luggage, with no particular preference for two or four wheels. As far as he's concerned, his carry on just needs to "fit in the overhead bin, have enough room for clothing, and have easy access outside pockets for travel necessities."

We spoke to a number of travelers, both frequent and infrequent, to get their opinions about carry on luggage. Between them, they use almost every type of carry on conceivable. Their comments reveal some interesting points.

• Hard-shell suitcases provide protection against wet elements like rain and snow. If you travel in poor weather, you might consider a hard-shell carry on.
• Brightly colored or flashy luggage stands out on the carousel at the airport. If you want to hasten your baggage claim experience, you might prefer a brighter color.
• A carry on with an extending handle is convenient. Just make sure the handle is long enough that the bag doesn't clip your heels as you walk.
• A carry on with a versatile handle is even better. You can grab it like a “traditional” suitcase, or you can pull it behind you.
• If you're interested in saving space and/or having rapid access to certain items, a carry on with netted or external pockets is nice to have.
• Hard-shell carry ons rarely have outside pockets. This could prove to be a hassle as you pass through security at the airport. Also, the ribbing on a hard-shell case may make it more difficult to pack efficiently.
• If your flight is full, airline staff may decide to check your hard-shell carry on to save space. This is an inconvenience, to be sure. A softer carry on is less likely to be checked.

Many people love soft-shell carry ons for their useful outer pockets. But there's no doubt that hard-shell cases offer excellent protection. Business travelers in particular favor them for their ease of packing and durability over time.

What’s more, casual travelers often find that their duffel carry ons are subject to less airline scrutiny than their hard- and soft-shell counterparts.

As for wheels, many people prefer the mobility of a carry on with four spinners, but two-wheel cases receive their fair share of accolades, too.

So while there may be no “one size fits all” solution, you could certainly find the right carry on for your needs with a little forethought. The number of options on today’s market is staggering, but we believe that any of the five well-researched options on our shortlist would serve today’s consumers very well.