I have heard of these, but have no experience with any of them. I will be snorkeling not scuba diving, and want two things: not to lose my equipment, and to be able to take pictures of fish. What will best help me accomplish this? If it matters the camera will be a GoPro 960 and shooting in burst or time-lapse mode.
We have a Sony P&S that can be used underwater and what we're currently doing (as in today) in Hawaii is using a hair elastic around the wrist strap to tighten it against the wrist. It works great and this is while snorkelling in the Pacific.
In other words, I don't think you need to spend money on a solution here...
My use is a bit different -- I take a waterproof camera kayaking. I have a small carabiner connected to the strap of the camera, which I snap onto my life jacket. The strap is only about a foot long, and with the camera always connected to my PFD it's always within reach and I can easily maneuver to get the photo I want.
Disclaimer: I don't know anything about snorkeling. I'm guessing you're basically staying on the surface and just breathing through that tube thing because you looked at the float strap, so perhaps you wear a PFD, too. If incorrect, an extra $0.02: you don't want a float strap because it's always going to pull the camera up and away from you.
Our friend took my daughter's waterproof Olympus camera on a cruise, and as a condition of borrowing it she bought one of these float straps — the exact one you link, in fact. This successfully prevented the camera from being lost during a "swim with the dolphins!" event.
It's a little bulky, but also has a clip that detaches easily (but reasonably securely) so you can just attach that part when you're going in the water, and use the camera without for the other parts of your trip without fiddling with attaching and removing it.
And it's not horribly awkward in use — and, amazingly for a photo accessory, at under $10 (from Amazon or Adorama) the price is reasonable.
I also have the olympus strap linked above, which I use with an olympus TG2. The bouyancy is just right for the camera near the surface, so it doesn't get in the way of taking pictures. I too dive down when snorkelling and down to around 5m it still works ok to make the camera float up, however, I have also used it while scuba diving down to ~12m and at this point the foam in the strap is compressed to such an extent that it no longer has the bouyancy to float the camera.