Sponge filters are a great alternative to HOB filters. I don't use any HOB filters in with my bettas. Everyone has long tails that get blown around no matter how low the flow. I will probably never use an HOB in anything smaller than a 29 gal again. I love the level of flow it puts out as well as the added filtration.
The one you pictured is a great sponge filter. The only other things you would need are an air pump and tubing as sponge filters are air-driven. I highly recommend it. The only downside is the noise of the bubbles. If your tanks are in your room, it can get a bit overwhelming if you are used to silence, but you get used to it after a while.