It's response has a dip in the midrange; so it's less pronounced / forward in certain midrange frequencies that might otherwise accentuate the nasal quality of a given voice.
You'll hear terms like "Midrange scoop" and "smiley-face curve."
The V67 is different, because it's scooped more in the upper midrange (between 2-6 khz), which effects articulation and "bite" more than anything, hence why some people think it sounds dark. The DF on the other hand, is scooped more in the mid-midrange (around 1K), and rises back up in the 2-3 khz range (more bite, less bark).
Those who like the v67 are generally people who don't like the sound of their own voice, because it basically takes any of the natural character right out of it, and replaces it with cheap Asian-made electronics.

I'm only kidding. Kind of.
You could just use a parametric EQ and sweep around until you find the area where your voice is giving you the most trouble. Generally, for a nasal voice, you might start somewhere around 1khz first ... and for a thin/squeaky/edgy voice you might try around 2-4 khz first (or better yet, the "mute" button). If the EQ works for you, you could just skip the new mic and go that route. Or you could start researching the plots, and look for mics that have dips in your trouble range. Generally speaking, you might want to try and avoid dynamics, as they tend to be more aggressive in the midrange frequencies that nasal singers have trouble with.
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