Mons. Adolphe Jullien, the well-known critic, somewhat severely sums up the measure of the composer's talent in the following words; "The principal talent of Mons. Thomas consists in having been able to bend himself to the taste of the public by serving up in turn the style of music that suited it best. Very clever in his art, but without any originality or conviction of any sort, he began by writing opéra comiques imitated from Auber, and pasticcios of Italian opéra buffa imitated from Rossini (such as "Carline" and "Le Caïd"); he then attempted the dramatic opéra comique, after the manner of Halévy, in the "Songe d'une Nuit d'Été," and "Raymond." Later on he did not disdain to compete with Clapisson in writing "Le Carnaval de Venise" and "Psyché"; then, after a long period of inaction provoked through several repeated failures, during which the star of M. Gounod had risen on the horizon, he has attempted a new style, imitated from that of his young rival, with "Mignon" and "Hamlet." In one word, he is a musician of science and worth absolutely devoid of artistic initiative, and who turns to all the four quarters of the winds when these blow in the direction of success."
These words contain undoubted elements of truth, inasmuch as they accentuate the fact that Ambroise Thomas' talent partakes largely of an assimilative nature. Notwithstanding this, there is a certain degree of personality evident in much of his music, discernible through an indefinable touch of melancholy that imparts a measure of distinction to many of his works, which can be sought for in vain amongst the compositions of his more immediate contemporaries.
Ambroise Thomas is one of the last offshoots of a brilliant period, showing in his later works indications of a desire to follow the new movement, without possessing sufficient strength to do more than make a feeble attempt at breaking through the bonds of operatic "routine," and ridding himself of the tyranny of the vocalist.
His work is unequal as a whole, but there is sufficient good in "Mignon" and "Hamlet" to atone for many weaknesses, and it is through these operas that his name will be handed down to posterity.