I took years of music theory classes while at both Missouri University and Indiana Jacobs School of Music. I find that Roman numerals are the most useful method of chord charting, here is an example:
I IV V I
An unbelievable amount of songs use that chord progression, it has some roots of popularity from blues music. The numbers are 1 4 5 1 not as useful though, because an upper case numeral means major chord VI and lower case vi means minor, as seen in this progression:
I vi IV V
I find it incredibly useful because the key does not need to be known to understand the movement of the chords. As a songwriter and producer I am changing keys often so the chords may end up in a different key anyway. I need to know how they move relative to each other:
I vi IV V
G major: G e C D
D major: D b G A
B major: B g# E F#
You could switch that to minor:
i VI iv v
g minor: g Eb c d
d minor: d Bb g a
b minor: b G e f#
