[0.15 lb] Totally awesome! Pretty much the closest filter to the Alexa look!
Very subtle, doesn't affect colors, and attenuate skin blemishes while retaining overall sharpness. Perfect to refining the cinematic look of your digital camera! This filter is always on my lenses as my default look.

[0.15 lb] I bought the filter for two specific shoots. Both went well and I have no complaints. I used the filter on my 77mm Canon 17-40mm L for shoots early morning and late evening in the Fall Colors and the results were fantastic. Would recommend to others. Didn't find anything I didn't like.

[3.5 x 3 x 1"] I am a fine atr / abstract photographer. I use this Warm Black Diffusion filter for still life, portrait, landscape and even shots of buildings and vehicles . The color tones of my subjects are very soft...also have an almost ebony hue to them. I seldom use Photoshop...I still love using lense filters. What's not so great? I cannot think of anything right now.

[3.5 x 3 x 1"] I love these filters, and I have the FX2 on all of my lenses for wedding videography. I like how it softens faces and reduces fine textures without adding any halation or losing contrast. My only gripe would be the artifacts in the filter are pretty noticeable in the bokeh or when the lens flares, but that's easy enough to work around.

[0.15 lb] If you're looking at this filter you likely already know what it is for, and sure enough it does exactly what Tiffen say. Optical resolution drops down but contrast loss and halation are kept to an absolute minimum. Strangely, if you look at Tiffen's triangle of diffusion diagram you'll see they put this filter halfway between resolution reduction and halation, implying you will get some soft highlight spreading. You absolutely do not and I don't know why that particular diagram suggests it when all their text and videos say it doesn't cause halation and, as I said, in use it certainly does not.
Allegedly on wide-angle shots or when using very small apertures you may see the black dots in the image. I can't say I've noticed this myself, but I only use this for shoulder-up shots, typically 50mm, often at fairly wide apertures, so I'm not in that 'danger zone'. If you want to shot wide and stopped down, maybe take caution and check out the Digital Diffusion/FX instead, which is meant to cause the same resolution drop without the black dots getting in the way.

I've had some limited experience with some Tiffen filters having poorly-cut threads, but otherwise the construction quality has been fine. Can't guarantee you'll get a faultless one but the fault rate, in my experience, has at least been very low – about one out of twenty filters having an issue, and even then, not one severe enough to stop the filter from mounting and functioning.

[58 mm] I bought it for video to have smoother images but I discovered that I also like it very much for portrait photography to smooth skin without having the dreamy halo effect. To my taste, the effect is very subttle, though...

[58 mm] This filter gives just the right amount of warmth to yield stunning but realistic flesh tones. Highly recommended for all kinds of portrait shots and anywhere that flesh tones are key to the photograph. Very solid construction feels high quality in your hand.

[58 mm] One of the best portrait filters I have ever used.Skin tones are softened beautifully,small blemishes and wrinkles disappear while leaving everything sharp.

[3.5 x 3 x 1"] The golden glow this filter adds is beautiful! Magnificent on sunny days and blonde or fair skinned subjects!

[58 mm] This Gold Diffusion FX 1/4 is a very nice filter to take the edge off digital. A golden glow is added with no or very little halation and I use it at outdoor parties and blond portraits.