I've had that Emgo box, and the Givi box. Had them on different but very similar bikes.
I liked the Emgo box itself at the time (she was my first!). It seemed to be fairly durable. Problem with that box was that the mount broke. I would carry groceries in it, so was probably overloaded at times. I ended up bolting it to directly to the bike, and then it was fine. Was just lucky that I didn't lose it when the attachment broke.
The Givi never broke, and had probably longer but similar usage. I don't remember if the Emgo box leaked, but the Givi did. The box seemed kinda flimsy, and I didn't realize it at the time, but for my use I much prefer a "square" box. The Givi was this weird rounded shape that makes it hard to haul anything with shape to it. Works fine for clothing, rain gear, or the like. . . .