IME this is one issue where feedback from other people is only helpful to a point. We're all different, our build varies, so a backpack that works great for someone may be totally inappropriate for somebody else.

I own a number of backpacks, some cheap, some in the higher price range. You do get what you pay for as far as the construction and materials go. But fit is even more important and it's highly specific. The backpack that fits me best is actually a midrange model. I have a couple of packs that are supposedly "better", but they just don't fit me properly no matter how much I adjust the straps. Which means lower back pain and an altogether lousy experience on longer treks with 20+ lbs.

30 liters is pretty small so the pack isn't going to be very heavy even when fully loaded but proper fit is still critical if your buddy does any long range hiking. My advice would be to do some research but definitely try the backpack in person before you buy it, hopefully with some weight inside. This is just one of those things that are best bought in store rather than ordered online.