I use an AT 4033. It is a very good mic for the price, and the difference between it and an SM58 is pretty incredible. However, I also use
a Beta 58, which is kind of a higher output, slightly more present SM58.
With the 4033, the first thing you'll notice is how you hear "more" of everything. Next you'll notice more highs, and that they sound sort of smooth, as opposed to the way the high highs in an SM58 just sort of taper away. Also, the proximity effect is a lot more noticeable with the 4033, and probably any large diaphragm condenser. Get close to it, and your voice gets that super phat low end. Even female vocalists can benefit from this, if they have sort of thin, airy voices, and you want them to be a little thicker.
That said, the 4033 is not a perfect mic. It can sound a little crunchy to me (and not in a tube distortion way) especially because i often record very loud rock singing. Also, on mroe distant recording or quieter vocals, the sibilance can be a little distressing, I often find myself de-essing afterwards. But for a $350 mic, it's one of the best out there. Although, now that it's out, you may want top check out
the Rode NT1000, which has been getting nice reviews...