I love this stuff not for what it does, but for what it doesn't do. It doesn't really float, which means that I have more control over the depth of my nymphs. You can make it float by forming it into a ball, but I usually stretch it out over my line so it sinks with my flies. It doesn't fall off easily, which means I can use the same small piece for entire days. It also doesn't spook the fish. In fact, when I have fish start striking it, I use it as a sign to start switching up to dry fly or terrestrial. Finally, it doesn't kink my leader. I hate kinked leaders.
What it does do is help me catch fish since I can see my line and what's happening to my line a lot easier.
For $7.50, go out and buy yourself a container and give it a try. It's one thing I always have with me and use every time I go out.