Hi I am going to give you my opinion although people will disagree. The artificial rock may look better short term than the white rock but with time the white will look the same. The artificial rock is hollow and dirt gets trapped inside. I know bacteria will grow on anything and that is all the artificial rock will be good for as for filtration I didn't think it gave the same result as real rock. The colour of the artificial rock fades after a while so to get the rock for that purpose will be a loss.
I never had any problems in my tank with live rock but on both tanks that I started with artificial rock I could not get the same result and always had diatoms or slime or something that would not go away.
I personally think nothing works better than the real deal.
It might take longer but the end results are far better.