A great product that does what its supposed to... keep all your items totally waterproof.
The 30 litre bag is huge! You could probably fit a small child into it, not that I would recommend that. It has a unique closing system where there is no zip. Rather you roll the top down and clip it into place. At first I had my doubts as to whether it would hold in place, but it definitely does the job.
I use this to keep my belongings dry whilst commuting on my motorbike. I've been through some serious downpours and the contents have always emerged totally dry.
It loses a star for a couple of reasons. Firstly, there is very little in the way of padding. So I'm reluctant to put my laptop in it as it would not protect against knocks. However, being the 30 ltr version, there is more than enough space to put an entire laptop bag within it... so that's a do-able workaround, even if it does add to the weight.
Secondly, there aren't any compartments within the bag aside from one small zip pocket. This makes finding items a real chore. Imagine it being like a big bin bag... you inevitably end up having to tip it over just to find what you're looking for.
All in all a great product that will keep your items nice and dry.