Here is a little review from the one I got a little while back. Sorry for the late reply on this...work has been a bit nuts and I have been on the road a lot...
Only $20! It is a very solid, not cheap feeling piece of equipment that I don't feel bad about putting into my tank. I don't see any obvious flaws in manufacturing, nothing looks or feels like it will have a short life, though only time will tell (as with any piece of aquarium equipment).
Great that someone finally put together a much cheaper, more ergonomically efficient (and much smaller) way to accomplish that of the big old sea swirls that have been around forever. I have opened up a sea swirl before, soooo much wasted space, and with so many more attention going to rimless tanks showing less and less equipment when possible, getting that big old cable box off of the tank is a big plus. And at a fraction of the cost!
Pretty quiet. Noise wasn't an issue in my case, and I don't foresee it being one unless the unit hits the glass and rattles or something (which it hasn't done yet).
I like the flow pattern, going slowly across one way and about twice as fast on the return. Good thinking. If only the flow could be angled/adjusted....(more on that below)
Negatives/room for improvement:
The cord seems a bit too short at only 5'. In order to add a proper drip loop, with both my display and frag tanks, that cord length is too short to have much extra for a loop in my case.
Mount/suction cup and assembly in my application with bulkheads and hard plumbed returns is generally worthless. As we all know, suction cups and reef tanks are never good long term solutions (unless this is some new fancy suction cup that doesn't break down over time, not holding my breath there), but I would imagine with a little DIY you could rig up some magnets or something else. I would think a majority of people wouldn't even need the mount, but there may be some out there who can use it.
In order to hard plumb this into my bulkhead fitting, it takes some work. My case may not be typical, so it entirely depends on each persons return plumbing. The unit needs some space in order to fit the elbow out, so in order to mount this relatively flush...kinda hard to accomplish. In the frag tank my pvc return comes up and over the overflow box, but fits too tight against the edge of the overflow to mount as close as I would like. So I need to add more length to the pvc return 'U' if you will, in order to mount this to it. Hard to explain this where it makes sense, when I get off the road for work I will snap a couple pictures that hopefully explain this better.
As mentioned, the mount isn't really needed anyway if hard plumbed, which is the case for me. Also the mount/bracket has what I assume to be a stainless steel rod allowing the bracket to pivot. Works well in that regard, but we will see if rust is an issue long term (I am not sure if the rod is stainless or not). I guess time will tell on that for someone, because I am not using it, I wont be that guinea pig. Also, the unit slides out of the top of the bracket very easily. Not an issue I would imagine once installed, but its a PITA until that point. Again, not that big of a deal once installed, but worth mentioning.
The biggest negative, and ultimately only one that means enough to me, is the wide diffuser. I have become spoiled with loc line, giving me the flexibility of adding on flow accelerators, or smaller ends to force and project flow a bit more than a normal wide opening allows. The wide birth on it just sort of spews the return water/flow out but doesn't reach nearly as far as it could/should. To me that half way defeats the purpose of rotating flow, if the flow cant rotate far enough to reach much. It would be a HUUUUUUUGE improvement if I could add my own PVC or loc line fittings onto the end of this. And for this reason, I wont be using this unit in my main display right now (unless I get creative and find a way to modify it).
Don't let the list of negatives misguide though...for $20 this little guy is hard to beat. Working in an engineering role I always look for improvements to be made, so I wanted to pass along some of the little 'gotchas' that I encountered. This will be running on my frag tank, as I am pretty content with the flow patterns I am getting in my display currently. If I am able to find a way to choke down the diffuser to blast the flow further, I may look to put one in the main display. Think a little bit about your own plumbing to see if its something you want to fiddle with (when DON'T we want to fiddle with our tanks, hehe), but also do not hesitate to pick one up and try it out. I have spent far more than $20 over the years on random little things that I think can make an improvement in my tanks, this is a pretty good buy. In fact I could see them easily charging 2x as much and it not stopping most people from grabbing them.