Enter Topaz Clarity. The question many of us have is whether it is better than Tonal Contrast. My early answer is that I can get very similar effects from both.
You are right, we already have many tools available for efficiently improving our perceived image quality. We can even do it less efficiently, by e.g. dodging and burning on luminosity masked selections
of our images.
Clarity has many more controls (34 sliders in all!) which means that it could give 'better' or more varied results - it is on the other hand harder to use imo and requires a longer learning curve. For instance it controls Micro/Low/Medium/High contrast separately - I am struggling to refer those to specific areas in the image.
I agree, it also took me a day of experimenting to get a feeling for what I needed to do to achieve my intended goal. The difficulty is that the controls have a somewhat different effect depending on the local image content, the effect is adaptive. It would also be a mistake to think that this tool will be all that is required, it is not.
IMHO, (Topaz) Clarity is the final step, after prior CA/detail/noise adjustments, and more basic Color Balancing and Tone-mapping (making sure that shadow and highlight detail is present and overall color and contrast are where they should be).
I am also not a fan of the existing presets, which I found myself tweaking a lot to get the desired result.
Be glad, it will allow you to set your work at a different level compared to the larger audience which Topaz Labs has to satisfy. Besides, using some of the less extreme presets, but at a reduced opacity will often get you pretty close to very nice results. They are also a good tutorial to consider (or reject) for you personal presets.
For example, creating a nice Landscape preset for different seasons, with an additional HSL Pop variant for the specific seasonal colors, can give very fast results that need only minimal tweaking. Clients usually do not pay for the time you need for post-processing, but they do notice if your images look better than from other sources and if you can deliver fast results.
The built-in Hue Saturation and Luminance filter is nice (don't we have that in ACR?) as is the masking capability (a toss with Control Points, which I think I prefer).
I've always considered the lack of control over the automatic masking (although it does seem pretty good) process a drawback (combined with the price before Google took over), which prevented me from getting on the Nik train. Also the first versions caused a lot of instability problems, judging from the comments on various fora.
Despite the fact that I am a big fan of Topaz Plug-ins (InFocus, Denoise, ReMask and B&W Effects being often used favorites) I can't help thinking that at other times they try to do too much in one plug-in, and that they would be better served breaking them down into smaller, easier to understand and use, narrower purpose units (like CEP4 does?). BTW, Tonal Contrast is the only filter of the Nik Collection I use.
There is some overlap in functionality between some of the Topaz Labs plugins (although Clarity is pretty unique), but that also stems from their business model. They need to attract new customers, and hope that those customers will also buy (some of) the other plug-ins once they get a taste of some of the features for which a more in depth solution exists. This is also caused by their policy so far, to supply update and
upgrades to new versions for free to existing customers. They need to grow their customer base. That also means that they need to keep on innovating in a customer focused way, I mean really
innovating! I'm more than willing to stimulate that innovation by my humble monetary contribution.
Contrast is everything in photography. An image with no contrast contains no information. So the ability to control contrast is key to a photographer's ability to convey his/her message. TC does a decent job quickly. Topaz Clarity could perhaps do better job but with a lot more work. I need to play with it on many more images before I decide whether to buy it or not.
I agree, contrast (IOW light quality) is what defines a superior image, assuming it is composed and timed correctly and it has an interesting subject. Topaz Clarity's power is growing on me as I revisit some of my prior work. As always, it takes a bit of practice to get better results, but the potential is certainly there.