19-EDO tuning is a meantone tuning, an equally divided octave tuning, a good diatonic mimic, and a chromatic-like tuning.
Meantone:
A meantone tuning integrates the error between the octave and the fifth into the rest of the tones, by taking a fraction of the comma (defined as the smallest discernible ratio of frequencies 21.51 cents). The error between the fifth and the octave in 19-EDO is almost exactly 1/3 of the comma, at 7.22 cents.
Diatonic mimic:
Since there are 27 diatonic intervals, including diminished, minor, neutral, major, and augmented tonalities, some intervals won't be uniquely represented in 19-EDO, but all of the major and minor intervals are very well approximated, putting it on par with 12-EDO (conventional western tuning).
Chromatic-like:
With a step size of 63.16 cents, the minimum step size is between the just diminished second (41.06 cents) and the just augmented second (274.58 cents), and there are more than eight tones per octave, it is a chromatic-like tuning.
Tables:
JI vs 19-EDO modal intervals (difference >21.51 cents [comma] highlighted red)
The tuning provides an acceptable approximation of all modal intervals, but the augmented fourth and diminished fifth are less than spectacularly close approximations.
Let's look at the same table for conventional 12-EDO tuning:
All modal intervals are closely approximated by a tone within a comma. The augmented fourth and diminished fifth are both approximated by the tritone in this case.
Adding in the expanded tonal intervals
Most of the extended tonalities are not so well approximated, just outside of the comma, but each one of them is approximated, and done so uniquely from the modal intervals. 12-EDO just doesn't do that at all.
While other tunings offer better approximations of these intervals, they may also add a lot of chaff intervals. Looking at the entire package, 19-EDO's ability to approximate each relevant major, minor, diminished, and augmented interval makes it a strong alternative to 12-EDO conventional tuning.
The down side:
There are many popular intervals associated with microtonality that are not out of familiar Western music theory. Neutral intervals are the particular example of tones associated with classical Eastern music theory, and those are not at all well represented by 19-EDO. To access neutral intervals with a strictly transposable tuning, there is no doubt that 24-EDO will provide an excellent palette of all the intervals necessary for Arabic and Persian modal music. Since there is rarely a need for the same neutral intervals in all 24 keys, hybrid systems of 12-EDO/24-EDO can also be very well utilized to achieve an Eastern-sounding composition.