My first backpack was a North Face internal Frame Backpack of which I used for a year, gave it away and purchased a JanSport D3 External Frame Backpack.
After 37 years, I still have and use my JanSport D3 on backpacking trips.
The features I found beneficial:
Comfortable weight distribution.
7 zippered compartments.
Ample external lash tabs.
The JanSport D3 has done the job, and then some, on all of my 4 season backpacking adventures.