On the downside, any water that does get to the zipper gets right in and it's likely to get back out. I wish this bag had a scupper valve or some type of weep system to allow water to escape.
If you need a bag to keep things handy on your yak this bag will do it, take it out and clip it on top of other gear in your canoe or even onto the bow.
Baja deck bag... don't hit the water without one.
I am pretty satisfied with this product. It's certainly very rugged. It holds an awful lot of stuff---jacket, lights, camera, binoculars, hat, etc. Convenient features include the carry strap, exterior mesh pocket for your sun glasses etc., and the bungees on top.
I have only one problem with this bag---the attachment system isn't all that secure if you have typical deck bungees crossed in an X. While the velcro strips on the bottom of the bag are long and strong, I'm not sure that's enough to keep the bag in place in rough conditions or if you capsize. It's also a little bit laborious to attach this way.
Other than that, this bag has cleaned up my cockpit considerably and I'm happy with it. It doesn't obstruct my view as I had feared. The only thing I keep in the cockpit now is a food cooler, so it can be out of the sun.