This bag is overall fantastic. It's proven really useful for me for commuting to work as it's one of the few panniers that can safely hold a laptop or iPad. Most are just nylon shells with no padding-this has myriad pockets, padding, zips, etc. It's a great bag, and it's wonderful being able to convert it into a backpack.
My only complaint is that some parts of it feel a bit cheap. The backpack straps, for example, have no padding at all. And some of the internal zippered compartments are good, but a bit thinly covered and can bulge into their surrounding compartment. Also, the bottom strap on the back of the bike flap (for connecting to the bottom of the luggage rack) is cheap, inflexible plastic, not a bungee or anything more sturdy. It hasn't broken yet, but I expect it will.
Overall a great bag, decently spacious and a good amount of pockets and such. But could use just a touch more quality and attention to detail.