I have one and use the finer blue filter. I bought it to remove any larger sediment during transfer after I had issues with a beer out post getting blocked with hop debris that I transferred across. It is really overpriced for what it is, especially as you have to buy a set of filters to get the finer one, but it does the job well, I usually find a fair bit of gunk in the filters when I clean it and there will be no way any dry hops could make it through. I also bought some 1/2NPT to 3/8" JG fittings so I could do the transfer with 3/8" liner instead of flexible tubing. I have used it at about 15psi for pressure transfer from my snubnose and it held (after sorting a few leaks). The long flat gasket between the 2 main parts is starting to deteriorate on mine, not looked yet but hopefully these are easy to find.
Doubt it would work well as a hopback as it clogs quite easily, Id guess any more than about 10g hop pellets would block the filter.