First let me say that I'm not a professional photographer, just an enthusiastic amateur.
My main subject matter would be portraiture but landscapes come a close second. I travel within my own country extensively and with such diverse landscapes it's hard not to click away constantly.
I use DCF on all photographs, just to see the effect it has, sometimes I'm pleased, others not. It's not a panacea.
The default settings are fine 95% of the time. At other times fine tuning is more experimental than practical.
Yes, shadow detail is lost at times (using default settings) but this can be remedied, using DCF and other plugins and/or graphics software.
DCF Full Spectrum was a gift. Had it not been I doubt whether I would have purchased as there are other, superior products available IMHO.
The plugin works, for me, more successfully on landscape subject matter than it does on portraiture, however, the subject MATTER is of more importance to me than the colour accuracy. We all see things in different ways, therefore, what's good for you maybe not for me. It's all very subjective.