A while back I was on the clean run (www.cleanrun.com) site replenishing Teller's PowerBoost supply and happened to flip through the toy section and sub-category 'floating'. I ended up buying a few sets of the smaller puller rings (which are a pool staple now) and the goughnuts stick.
For pool toys I do like the puller rings - they float pretty high in the water, they're light and they're highly visible in the pool (and lake too). The dogs do like them but for swimming I caution against using the larger puller rings. Several times my dogs have gotten legs - or heads - through the larger rings and I'd be very concerned if this happened in a large body of water.
I didn't like the goughnuts stick at first - heavy for its size it goes a bit further than I expect it to go (which means I can inadvertently throw it out of the pool. Marketed as a floating (and indestructable) toy I wasn't impressed with the floatability of the Goughnut. It's more of a bobbing toy than a floating toy. Once thrown, it will eventually float to the surface but not immediately so. The dogs however seem to like this feature, Kipling in particular likes to dive for it on his jumps. I'm actually debating using the GoughNuts for Kippie's dock diving competition in a few weeks... And well....Kippie, what do you think?
Also, the darn thing is guaranteed forever if your dog manages to kill it. That's always a plus!!