I just ordered a Mühle Sophist Fusion and DE set with bowl and a Silvertip badger 23 mm brush but the lady from the shop claimed that Silvertip Badger brushes are the best for creating and applying lather - no contest. What surprised me was that she said it wasn't the best brush for lather painting and massage of the lather into the skin. Is the right or wrong here ? She claimed the Fine Badger brush or one of the new Prime Synthetic brushes is better for lather painting and massage. Is she full of it and just want an excuse for selling me two brushes or does she have a valid point here ?
Both. The texture of brush and the face of the user causes so many different opinions. I like a slightly scratchy brush (little scratch) while others want smooth butter to paint. She is more than likely giving you feedback based on a limited sample of customers. Good fortune and realize that you may go through more than one brush. Read some of the posts on the site about brushes and while you are reading think about your face and what sensation you will like. That can give you a better start point to understand.
We could argue this one for a long long time. It comes down to personal preference in the end, you find what characteristics you like in a brush and go from there.