It's not fantastic quality. Its plastic not leather but I knew that when I bought it. It is pretty inexpensive. I wanted this bag as a handy shoulder bag to use when I have to take something on my motorcycle that doesn't warrant bungee-ing onto the back - and those plastic box things ruin the look of classic BSAs and Triumphs. I liked the look of this bag as it looked like the sort of thing I used to take to school back in the 80s.
I am very happy with it. So far it has proved to be fairly waterproof although I use a polythene bag on the inside helps keep any books or maps dry. There is room for a small socket set, couple of screwdrivers, waterproof pants, sandwhiches, thermos flask and a map and a book and whatever motorcycle parts I have been helping my mates out with on the day. I like it. It looks cool too.
The shoulder strap is sturdy enough - these days the stuff I carry is a little heavier than the school work which I never used to do anyway :(
My daughters have their eyes on this for school I think so I may have to buy a couple more in different colours.