Although I proportion the Persil Megaperls low, my Cottons is always bright white and without spot from the washing machine - even the soccer jersey. The fragrance smells "clean". I particularly appreciate that the laundry with Persil gets no gray haze after many washes, but will remain a bright white. I can not say of many other heavy-duty detergents.
Conclusion: Persil is more expensive, but from my personal point of view is actually better than a lot of low-cost alternatives.