The most I've lugged a Bergans pack continuously (meaning no vehicle rides) was a week long back country trek over the continental divide in the back country of Montana. I was carrying about 45 pounds. It would have been a far more enjoyable trip with a more modern pack, and it was after this trip that I picked up a Kelty frame pack, which was a vast improvement for extended treks. As I said earlier, I still use the Bergans packs a lot, mainly because they are far less bulky and more vehicle friendly than a full frame pack. For day trips with a light load, the Bergans pack is perfectly adequate, and a far cry better than the glorified book bags a lot of people carry. The Bergans pack can also be worn while riding a bicycle or motorcycle, don't know whether that is an issue for you or not, but good to know. I have also found the Bergans carries well while cross country skiing, but I've never used the Kelty in that role, so I can't offer a comparison. I've never considered putting a belt on one, I've got the Kelty for the heavier loads, so why bother?
For the price and your intended use, I'd say you'll do okay with one.