I have the Phos-Reactor by Kent Marine. Mine is an older version than what I see online now, but the design looks the same. So, assuming nothing was changed from the old model to the "new" model, I can tell you that it works just fine. I will agree that the filter pads in there could be a finer material, but the fact is that they would clog more easily if they stopped every piece of "dust" from the media. With low enough flow, you won't have to worry about shredding your media and having particulates getting into your tank. If you worry too much about it, you could just put your carbon or phosphate media or whatever inside of a filter sock; I've done that before with good results.
Overall, I really like the Kent Marine Phos-Reactor. The only thing I would say about it is that you shouldn't try to force too much flow through it. I run a Mini Jet 606 on mine and it works just fine. I also think you could use a Maxi Jet 400, but I wouldn't go any bigger than that. You just want enough flow to make the top of your filter media bubble gently. You don't want it to fly around in there and grind itself up.
Hope this helps,
Joe