As a sea kayaker who paddles…
As a sea kayaker who paddles day and multiday trips, a see through dry bag is the only way to go in my opinion - I can see what's in the bag. I have a 5L Glacier Bay and have used it for a couple years in hot and cold weather. Works great.
I'm new to kayaking and recently took a 4.5-hour kayaking course that included rolling my kayak, but I managed to roll it before we got to that part of the lesson! I had my smart phone and wallet (among other things) in the new Seattle Sports Glacier Clear Dry Bag I just purchased, but did not have it lashed to my kayak, so when the kayak rolled, my bag ended up in the bay for several minutes. Once I got the kayak righted and myself and all my gear back on board, I fearfully checked to see if my smart phone and wallet were okay. I was relieved to find that they were absolutely dry! I was sold, and I plan to purchase more bags from Seattle Sports for my future kayak adventures (as well as some leashes or clips to secure them on board my kayak).