Influenced by the chord voicings employed by McCoy Tyner and the harmonic patterns used by John Coltrane, I began tuning his guitar in fourths (E-A-D-G-C-F, low to high) in 1990. Initially, this was intended as an experiment to explore the possibilities it opened up for more symmetrical scalar patterns and chord voicings than the conventional guitar tuning.
One of the immediate (and lasting) effects of this change is that standard bar chord voicings and open position chords are no longer workable options. As it turns out, many guitar cliches one takes for granted become significantly altered - making one realize that these phrases have become cliches due to how readily they fall under the fingers in conventional tuning — a convenience which is often not the case when tuning in fourths.
By the same token, the 4ths tuning lends itself to its own set of cliches spawned from certain types of more easily executed phrases and voicings. For example: Any chord voicing spanning 4 strings can be transposed by simply moving to any other set of strings without changing the fingering. Octaves, for instance, use the same fingering regardless of the string pairs being played. The same holds true for any scalar patterns - gone are the asymmetries resulting from the third between the G-B strings in standard tuning.
So, while tradeoffs include some oddities — say trying to cop a Wes Montgomery line or chord solo note-for-note may make certain voicings and fingerings more or less difficult than standard tuning — the symmetrical nature of the fourths guitar tuning greatly simplifies playing one of Wes' signature octave runs. Similarly, Coltrane's pentatonic and sheets of sound patterns are readily transposed anywhere on the fretboard without changing the fingerings.
For more updated resources & info on all fourths tuning, check out the
"Guitar Tuning in 4ths" facebook group