What makes a mic preamp good or bad?
There are three main characteristics of microphone amps relevant to this discussion:

Gain.  The output signal of different microphones varies a lot.  Electrets (with appropriate power supply and pullup resistor) usually produce a stronger signal than a bare dynamic or piezo mic.  Look at the datasheet, but experimentation may be needed.  From mic to line usually requires a voltage gain of somewhere around 1000, but could be a few 100 to a few 1000 depending on the mic.

Noise level.  This is probably your toughest criterion.  With audio, signal to noise ratio generally needs to be high.  Figure 60 dB bare minimum, and that's pretty crappy.  100 dB or more would be much better.

Frequency response.  "HiFi" audio is considered 20 Hz to 20 kHz, because that more than covers the range of hearing for most humans.  If you are only interested in voice signals, then you don't need such a wide range.  In fact, narrowing the frequency range then helps because it attenuates noise that can't be voice due to frequency alone.  Passable voice is around 100 Hz to 3 KHz, although that will sound noticeably squashed, like thru a tunnel.  50 Hz to 8 KHz is much better, and sounds pretty good.  Beyond that you add more frequencies that aren't really included in the voice, but are ambient sounds that make it sound more "live".  If you are trying to do voice recognition, you want to actively limit the frequency range, but probably not in the preamp.  This is better done later digitally where it can be done more flexibly and accurately.