No one can really answer the question accurately. What works for one will not for another etc... The differences between bio load, tank size, feeding etc... make it difficult to say one way or the other. Pot scrubbers (I have piles as well) are just surface area. They have far less surface area for the valuable real estate of an FX6 vs a traditional ceramic type media. So they will not be as efficient in a head to head comparison. Having said that if your bio load is not pushing the filter to it's max it's a moot point anyway and may be sufficient. Does that make sense?
If it works and your ammonia is 0ppm, then it is good to go. Bacteria aren't picky where they choose to colonize.