I have had this backpack for almost a year.
The materials are good. They seem durable and they don't have velcro in the hip unlike some other backpacks available in the market. Velcro is likely to wear and you have to replace it.
This is likely to be an issue in the case of the cords that attach this backpack to the bottom of the case. But you don't have to open them so often, so I don't expect this to happen in years.
I bought this backpack to use it with my 15-year-old Bam Newtech cello case.
I took off another famous system from Germany that started to fall into pieces after five years of heavy use. The system from Bam is lighter, you don't have to screw anything and you can find a place for everything you need for your gig, such as scores, rosin, strings, and even your mobile.
I highly recommend it for BAM cases.