A good hiking backpack should have the following features:

Comfortable fit:

The backpack should fit comfortably and snugly on your back, with padded shoulder straps, a supportive waist belt, and a well-ventilated back panel to reduce sweating and discomfort. For example, we usually adopted below back system for backpacks larger than 50 liters. Adjust the shoulders according to your torso-length, which make the backpack fit your body perfectly,then more comfortable.

Adjustable straps:

The backpack should have adjustable straps that can be customized to fit your body type and size.

Appropriate size：

The backpack should be appropriately sized for your needs, with enough space to carry all of your gear without being too heavy or bulky.

There is another article about how to choose the size of hiking backpack

Durability:

The backpack should be made of high-quality, durable materials that can withstand rough use and exposure to the elements.

Usually we use nylon fabric, because it is durable,ripstop and light weight.

And YKK buckles is perfect for hiking backpack, it is almost never broken.

Organization and Accessibility :

The backpack should have multiple compartments and pockets for easy organization of your gear, with quick access to frequently used items.

and easy access to gear and snacks on the go, with pockets or straps for carrying water bottles and other essentials.

Water resistance:

The backpack should be water-resistant or come with a rain cover to protect your gear from rain, snow, and other elements.

Weight distribution: The backpack should distribute the weight of your gear evenly across your hips and shoulders, reducing strain on your back and allowing for comfortable, long-term wear.

Overall, a good hiking backpack should be comfortable, durable, and functional, allowing you to carry everything you need for a safe and enjoyable hike.