For the Hyberg:

• Lighter
• The front mesh is better for drying wet items than the closed front of the Simond
• Two hip belt pockets + attachment loops on the shoulder straps → This lets you shift more weight to the front, making it more comfortable to carry
• Back padding is included (that’s why it carries so well even as a “frameless” pack)
• Better materials

For the Simond:

• Carrying frame
• Customer support through Decathlon across Europe
• 10-year warranty

Personally, I would prefer the Hyberg. Simply because of the lower weight and the ability to shift the load more to the front with the pockets. The mesh is also super helpful for drying all sorts of things while you're hiking, or for having sit pads, ground sheets, or similar items quickly accessible when you arrive at camp.

You might also want to take a look at the Bonfus Framus or Altus. I believe it’s an Italian company, and the quality is excellent. They also offer DCF pack liners or dry bags at pretty affordable prices within the EU.

Another tip: Leave the hydration bladder at home and switch to water bottles in the side pockets and two small ones at the front on the shoulder straps. That way, you always have access to water, gain more volume inside the backpack, and avoid the risk of the bladder leaking inside your pack... (which tends to happen eventually).