I think some of my images look like they could have been taken with Leica lenses. Even those without any filters. This may be because, in my moderate experience, the main factor that determines what a picture looks like is not the filter or the lens, but the scene that you point the lens at.
I bought the fancy filter spontaneously because I was appreciating the good service I got from the shop on another item (otherwise it probably would have been a cheaper brand). The price was actually quite reasonable (I believe about S$80 for a 77mm CPL).