I purchased one and have been using it for over a month. I am quite impressed when comparing it to the alternative methods of removing pests; no kalk paste, no tweezers, and no wet arms.
I use it to remove mushrooms, palys/zoas, sponge and trim sps. While it is a bit teadous, using it less than 5 minutes a day adds up quickly. The other reason for short sessions is the tool dosen't do a very good at sucking up the debris. Short sessions limit the amount of toxins that are released into the system.
While it isn't inexpensive, I do feel it'll last long enough to pay for itself. I'd love to see it with a bigger powerhead and built stronger, I do recommend it as is.