The media determines the effectiveness.
I used sponges from XP 1 that aren't correctly sized for it just to trap some particles, I bought it for the built in UV.
I also have an Eheim Pro3 running with only bio-filter because the maintenance on it is such a pain. The main intent of the SunSun was to kill the free floating bacteria or virus that was infecting my fish.
Now that the fish are healthy again, I will re-use the XP 1 w/ mechanical pads that was temp replaced by the Sun Sun. The XP 1 is easier to maintain due to the size and the Sun Sun barelyu fits in the cabinet opening. It's also a pain in the ass to start up. The priming pump is worthless but it does give my arms a good workout when it eventually pumps all the air out... It's nothing like the ease of the Eheim Pro3 primer where I only need to use a few fingers and slight pressure and I don't break out in a sweat.