What a great sounding microphone! I use this on male voice (my own). Its is extremely open and clear sounding, basically what you'd expect from a condensor mic (which the m80 is not). Works great in rehearsal and live gigs, but equally impressive in studio use. A big step up from my precious mic (Audio Technica AE6100).
Side-rejection is fairly big, and the microphone is completely unforgiving sound-wise, so no hiding behind a mic. Given its open sound, it does require some singing technique. Maybe not the best fit for a starting vocalist, or one who is used to move a lot around the mic (better go cardioid then). I think proximity effect is quite mild compared to various other microphones i've used in the past. Handfeel is awesome, all metal and sturdy, and its weight is a bit on the heavy side which i personally like.
To get the most out of it, it does require to open the gain a bit further on your mixer/interface/preamp, but then it totally opens up in a wonderful way!
In short: very impressive microphone and highly recommended