I bought one of these bags five years ago. It is still going strong and is my favorite bag. It can comfortably carry enormous heavy loads, looks in great shape for as much as I use it, and converts easily between pannier and backpack. I can see this bag easily lasting decades.
The downside is it is such an amazing bag that my daughter stole it from me and I need to get a second.
I recommend buying a reflective ankle strap to put on the Velcro in backpack mode if you have long hair. It was quite painful getting my hair stuck in it. Even if you don’t have long hair, the Velcro collects lint and more reflective things equals better visibility, so still get an ankle strap to put on it.