The first one I received, I had to send back because the strap on the bottom was not attached properly, and this strap basically carries all of the weight of the violin case.
The second one was better, but also here the safety strap (that goes around the handle for extra safety) is not properly attached.
It is impossible to position the fastenings properly because they're not in the right place; either one goes over the handle or one continually scrapes the lock on the case, and either the violin is placed really high or really low, in some positions resting on the fastening if stood upright. It would be better if the bottom strap were fixed, and the right lenght for the case. It would be more secure that way. There are too many adjustable straps that can come loose and that's not great.
The material of the backpack is very solid and sturdy, but it doesn't have a lot of space. It is quite comfortable to wear on your back though.