Air driven skimmers are more efficient, less noisy, require only an airpump, and can be made by you. Venturi skimmers out-do them because you can get a lot more into a smaller skimmer. But if you have the room and know how to make your own air stones, air driven is perfect. The problem with them is that they need to be large and require regular replacement of air stones. Thus, they are more expensive long term. They also require constant adjustment and regular pump maintenance for optimum performance. Under ideal conditions they are the best skimmers. But the real world isn't ideal ...
I know this skimmer. I have had a similar one on a 40 gallon tank. It was my second skimmer. I still have it today but I won't use it. For a 15 gallon tank, it would work perfectly fine. But for the price you would pay (compared to the quality of the skimmer) I would build my own air driven skimmer.
I don't know what these "cheaper" venturi skimmers are that others are recommending but for a little more money I would invest in one of the stronger skimmers that use a water pump.
If your tank is a reef, the quality of the skimmer is very important.