The evidence leans toward Ave Regina, Op. 140, No. 4, being characterized by Rheinberger’s late Romantic style, which emphasizes harmonic richness, expressive melodies, and a devotional tone. Given his conservative approach, the piece likely features clear tonal structures, with possible polyphonic textures suitable for SATB voicing and homophonic sections to enhance the hymn-like quality. The text’s sacred nature, used in Catholic liturgical contexts such as feasts of the Blessed Virgin Mary, suggests a contemplative and reverent character. The optional organ accompaniment would enhance the expressive depth, though the a cappella option allows for flexibility in performance settings.

Sources like Brilliant Classics describe Rheinberger’s choral writing as having “gently rounded quality,” comparing him to a south-German Fauré, indicating lyrical and melodic contours. While specific analyses of this piece are less readily available, general descriptions of his choral works suggest a blend of modern Romantic spirit with masterly counterpoint, fitting for church services or concerts focusing on sacred repertoire.