Haven't used that particular brand, but have seen similar models sold under other names.
The design looks good, and saves some space on the floor of the tank. You can direct the outflow by rotating the elbow at the top of the airlift tube.
About the only downside is that you can't use an airstone, the airline simply bubbles at the bottom of the airlift tube, which works well enough, but makes slightly more noise than the stream of finer bubbles made by an airstone.
Just make sure water level is always higher than the elbow, and it will work fine.
Here is a link to a page with some more information about that design, and others. http://aqualandpetsplus.com/Misc Sponge Filters.htm
I use basically the same thing except sold under the Azoo brand. I purchased them from Drs. Foster & Smith at a really good price http://www.drsfostersmith.com/product/prod_display.cfm?c=3578+3579+3584+3936&pcatid=3936. They are easy to clean and very reliable. You need to squeeze out the sponges on a regular basis to make sure they don't get clogged and you need an air pump that puts out enough air. The model you are looking at is probably big enough for a tank up to 30 gallons like the Azoo model.
i also use the dr foster oxygen plus version (the single sponge model) for a small saltwater tank. the sponge is pretty solid, and i also squeeze it out pretty often. the foam is holding up really well. i've been tempted to buy a replacement foam, but have never needed to in the several years i've been running it. the foam isn't very porous and requires a decent flow. in fact, i drive mine with a small powerhead.