I ride to work everyday and if I didn't already own an Ortlieb Waterproof backpack ($130) I'd definitely purchase one of these. It even has additional features that the Ortlieb doesn't have, such as:
- Reflective stripes
- Buckle (Ortlieb is only has a velcro equivalent which isn't as good)
- Hanging loops (Ortlieb has only a small hook)
Best of luck buying one!
Price in title OP