I really don't know why but I just kind of got it in my head a 48V Mike is just better from the gecko like a V6 engine being a little less to work with than a V8.
Ha! MUCH better men than I can school you on microphones here but this is MY potted history!
The main advantages of the Large Diaphragm Capacitor microphone are a high sensitivity (means a high output voltage for a given sound pressure. Commonly 10 times (20dB) 'hotter' than a dynamic. This reduces the low noise requirements in the pre amp for quiet sources though it has to be said, pre amps these days are really mainly good enough for most mics/jobs.
Perhaps even more important though is the cap' mic's wide, flat* frequency response. You can expect a good response down to 40Hz and up to 18 or 20kHz (I have not checked the SM4's specc. will do!) This wide response is coupled with low distortion. Capacitor mics are generally thought of as more "hi fi" than dynamics BUT! Mics are very much a personal choice, especially for voices.
The downside to that high sensitivity and wide response it that the mics pickup much more of EVERYTHING. This is NOT because of the operating principle. Give an SM58 20dB more gain than normal and it too will collect all the **** in creation!
With a dynamic though you can get in closer, like <50mm (pop shield!) and not 'blast' the mic. Not so with most capacitors. but, as I said, very close working will make your voice bassier.
Then we have SMALL d capacitors. Much the same applies as for their bigger bros but sensitivity is a few dB lower and "self noise" a little worse. Very usable on instruments mainly. My son records classical guitar with a pair of Lewitt 040s.
*Almost all LDCs have a 'bumpy' upper mid range with a presence boost from perhaps 4kHkz to 8kHz then level again out to 18/20k.
Dave.