Tunkel (2012) regards him as "the most important of the composers of synagogue music in the Anglo-Jewish tradition of the 19th Century" whilst Elton (2003) doesn't even restrict this assessment to England.
His compositions started from the traditional modes of synagogue music, but extended to include German and English folk song and contemporary classical themes.
However, at the Great Synagogue in London, Chief Rabbi Solomon Hirschell expressly forbade the use of sheet music (which he referred to as the "Book of Strokes") and the tuning fork.
[5] Following the Rabbi's death in 1840, the resulting change in leadership spurred on by Henry Hyman Cohen allowed a full choir to be formed the following year.
Some of his compositions, such as Mechalkeil for Yamim Noraim, Baruch Haba (processional), and Ladonai Ha'aretz (Psalm 24), have become 'standard' pieces in Anglo-Jewish communities, where they are still regularly sung.
Mombach's setting of Ma'oz Tzur is an arrangement of an earlier piece, parts of which come from a chorale by Martin Luther (the Christian reformer) Nun freut Euch Ihr lieben Christen.
Luther had, in his turn, adapted an old German folksong So weiss ich eins was mich erfreut, das pluemlein auff preyter heyde.
[4] Mombach arranged choirs for all the main events that took place in the religious life of the Ashkenazi communities throughout England, and many of his pupils went on to become cantors in English and colonial synagogues.
[4] Tunkel (2012) writing on the Zemel Choir's website, says that "Mombach is very singable (in melody and harmony) and it is for that reason that so much has indeed survived as the traditional backbone of Anglo-Jewish synagogue music.
Roth (1950) summarises his importance by saying that as a composer of synagogue music Mombach was equalled only by Solomon Sulzer of Vienna, and a large proportion of the now-famous Anglo-Jewish choral melodies were first familiarised by him and his collaborators.