If it's anything like the "Wall Whale" brushes I love mine and it's been working for 4 years now. I probably need to replace the brush head this season but the fin still works fine.
I think the fin style brushes are excellent and very effectively mix the water. Just be careful and go with a normal size. Wall Whale at one point made this XL style brush which was a very dense brush that was extra wide. It generated so much downward force and friction that most people could barely push it.
Brush work fine. Can one hand push forward and one hand pull if a long pull. As you shift from pushing forward, the brush float up. The bottom line is that it does add pressure to your brushing, but you can't go really fast. For $24 it's good but we'll have to see how long it last
My experience with this brush is mixed. The brush itself works well but the springs on the fin are total crapola. I had only used my brush a few times and one of the springs broke. I called the company and was told no warranty on the springs but was happily informed that I could purchase a replacement set (left and right springs) for something like 5.00. I went ahead since the brush was useless without the springs and it was essentially new. Well I was using it yesterday and only got halfway around the walls of my pool (20x40 NOT Olympic sized) and another spring broke. I don't know which spring it was but with any luck it will be the spare spring I have.
In any event, I wouldn't buy one again. Too high a probability that another spring will soon break and I will be out another 5 bucks or left with a useless brush.
I should add that I hate brushing and only do it a few times a season so overuse is NOT the problem and my water is always balanced so it isn't as if the water is attacking the stainless steel springs.