Interesting as I never heard of this brand, have you use it? good price too.
For non-film IR the frequency range is pretty specific. Only Hoya and Singh-Ray are in the running. Tiffen (argh) might be better than B+W in this case. Harrison might not have enough coatings but it's the right frequencies, better than B+W. You couldn't go wrong with Singh-Ray, and Hoya might not be quite as good but it's great, too, and with Harrison we're using old Canon FL lenses anyway so why not?
If you go to their website, you see lots of heavy hitter names like Galen Rowell. Their sales pitches make sense except a few basic filters where they are just band-wagonning because you're there and Tiffen would do for your basic mercury vapor light filter.
Their best sales pitches are the IR filter with what you can see are the perfect frequencies, and polarizer and neutral density filters that do not require as much light as others--about one stop less than others is a huge diff in low light.
The only filter I've used so far is UV. I thought I'd buy a pile of filters for Sigma 72mm until I run out of money, and then actually use a different lens size with UV filter and funny looking 72mm adapter. I thought that would be a bad idea but I was obsessed and did it anyway. I'm a filter-rich dilettante, haven't even used the IR yet. It kind of scares me to contemplate taking out the IR filter, and focus screen(to hack Olympus microprism split-screen to fit since Katzeyes aren't in production right now).
