Accessories for cameras have improved in both quality and function over the last decade or so, but perhaps not as quickly as other areas of equipment. This new filter system, however, aims to overcome a lot of the irritants around stacking filters.
When I first started photography I had a weird relationship with filters. For a while, I didn't touch them, primarily because I didn't understand them. Then eventually I bought my first — a cheap CPL — as I had read it could make long exposures of water look better. When it did in fact improve my image, I started buying a ton of different filters and experimenting. Almost all of them were worthless (I'm looking at your starburst filter) but a few had applications. As the years went on, I invested in better filters that I had specific uses for and they have always done what I needed.
However, I have lots of dislikes for filters. Many systems are cumbersome, graduated NDs can be annoying to fix if you don't have a straight horizon, and stacking filters has its own set of problems. For example, if you don't stack them properly, you can get diffraction or softness, and stacking properly can be tricky unless they are designed to do so. In videography this becomes simultaneously more important and more tricky too. This system reviewed by Peter Lindgren looks to be a neat solution.