Cotopaxi Allpa 35L vs. Millican Smith 18L

Let's start with the Cotopaxi Allpa 35L. When measured, a Cotopaxi Allpa 35L backpack has a 20" height, 30" width, and 51" depth—or in other words, it's a pretty big backpack. It's a bit hefty at 1.5 pounds, but it makes up for it with a whopping 35 liters of potential storage space. I mean, that’s about twice as much as a standard backpack. The killer feature, however, is its compatibility. Believe it or not, this thing will fit in the overhead bin of 80% of airlines. As if that’s not enough, reviews have been pretty positive about the bag's design, including its 1680D ballistic nylon paneling and pockets that can fit a 15" laptop. It even comes with a rain cover, shoebag, and collapsible mesh laundry bag.

Now, let's flip the chart to the Millican Smith 18L. This backpack is a tad smaller—51" tall, 28" wide, and 15" deep, but only weighs in at 0.9 pounds. It does have a little less capacity, but at 18 liters, it's still nothing to scoff at. On top of that, this pack is compatible with 99% of airlines. That’s right, it's nearly universal. It’s made of weatherproof bionic canvas and, like its counterpart, sports a 15" laptop compartment.

To better illustrate the differences, here’s a bullet-point summary:

• Size: The Cotopaxi Allpa 35L (20"x 30"x 51") is bigger than the Millican Smith 18L (51"x 28"x 15").

• Weight: Cotopaxi Allpa 35L weighs in at 1.5 pounds compared to Millican Smith 18L's lightweight 0.9 pounds

• Capacity: Cotopaxi Allpa 35L offers 35 liters of storage compared to Millican Smith 18L's 18 liters

• Compatibility with airlines: Cotopaxi Allpa 35L fits the overhead bin of 80% of airlines while Millican Smith 18L is compatible with a whopping 99%

• Material used: Cotopaxi Allpa 35L features rugged 1680D ballistic nylon paneling, whereas Millican Smith 18L is made of weatherproof bionic canvas

• Laptop compartment: Both can fit a 15-inch laptop

• Extras: Cotopaxi Allpa 35L comes with a rain cover, mesh laundry bag and nylon shoe bag. Millican Smith 18L is a grab-and-go, no frills pack.

For the eco-conscious, the Millican Smith bag might be more your speed. It’s made from recyclable materials, and despite its heritage design, it’s comfortable due to the back padding. This bag looks good whether it's empty or full. The Cotopaxi, on the other hand, wins in terms of sheer capacity—and the multiple storage compartments make it handy for the organized traveler. Plus, the rain cover adds an additional layer of security for whatever you're carrying. In the end, it really depends on what you're looking for in a backpack. Both are solid options, but I'm leaning towards the Cotopaxi Allpa 35L for the storage capacity and extras—plus, you can't really argue with 80% compatibility.