I bought a DiCAPac a couple of months ago before going to Greece.
I have mixed feelings about it to be honest. I tested it before going and tried it in the sea, and it worked very well to protect my gear. But it’s almost impossible to do anything other than pushing the release button and you can’t use all your lenses with it (adding the tube extension provided, the maximum length would be the same of the 18-55mm lens) or it might not be too stable if you have a lens whose diameter is much smaller than the bag tube (like when I tried the 23mm f2).
Of course you can’t play much with the camera while inside the bag so you need to have a clear and one-size-fits-all configuration applied before you put the camera in, which again could be an issue if you go down deeper underwater and the light changes.
Then, you ask about a bag that’s easy to open when you want to shoot, but you can’t open/close the bag with the lens attached: you need to unscrew the tube, remove the lens, then open the bag and get the camera body out… probably even more frightening uh?
So overall, good for peace of mind but not too flexible. Allows for interesting pictures in and under water.