I've used Hoya filters for quite a while now. I was previously using the Pro-1 models, and was generally very happy with their filtering qualities, but had problems keeping them smear-free. Enter the HD - these things are very well constructed and nicely hefty. The coating also works very well, and they are extremely non-reflective. They are just a cut above the construction of the Pro-1 filters. They also have the dual benefits of being very tough - offering improved protection over standard filters to your valuable front element - and most of all, they have a non-stick coating which just keeps smudges and dust off them so much more easily, often dust can just be blown off with a puffer, which usually wasn't enough with the standard filters. After getting one for my Nikon 70-200mm f2.8 VR, I've traded up across all my lenses. Highly recommended.