Given the weight and design
Of that Miele series, I would seriously consider concrete.
Those washers were originally intended for very solid floors like we have here in Germany, not the relatively free swinging pedestals which more modern, lighter suspensions feel comfortable on.
There were, however, pedestals made specifically for this model, and I can remember reading about them over at the garden site...so they made it to the US. Gosh, those people make our most "energetic" UK members look mild as lambs. What is their problem?