Pretty good!
I've only used this once so far and it's not bad. The strap is a bit stiff and can be a little thinner (including the width of it, it was hard to  have something in between my thumb and index finger when isolating) but other than that, I like it so far. The plastic tile is light-weight and adheres to the strap with velcro so you can easily adjust it.
Rating: 4 stars