First impression of these filters were they are well built with no play between the glass and the metal ring. On top of that, they were fairly slim, so the issue of vignetting won't crop up.
Both pieces of the Lens Protect filters were made to do just that - protect your lenses from finger smudges, incoming beer splashes etc.
Next up were the Circular Polarizer filters (Super and normal) both DHG. I tested both of them out to get the normal clear blue sky and couldn't really tell the difference between the 2. Both of them provided equal effect on the shoot. Besides from turning the sky blue, Cir PL can be used to "shoot" through glass or water reflections.Again built quality on the filters were top notch but I found the Super Cir PL to be of better built. There was a slight play on the normal Cir PL, not that it will affect any picture quality but I'm a fuss pot.
Last but not the least and I must say the favorite of the lot, we have the Light Control 8 filter which darkens everything or acts as a sunglasses for the lens. You will need this filter to get long exposures when shooting waterfalls, silky smooth sea effect etc. I use this filter a lot in landscape and even portrait shooting sessions when I need it to darken the background and then using strobes to light up the main subject.
In conclusion, the Marumi range of filters tested out, were well built and got the job done. The screw thread areas were well rounded and did not have any sharp edges as compared to those found in lower grade filters. The filter rings had a nice high quality black coating around them. You can be sure that these filters will not damage your lens filter threads from its excellent built quality.