This recording is absolutely worth it: Karina Gauvin's singing is shockingly beautiful.
Although the title tracks are noteworthy and probably the most memorable, every moment of both pieces gets its full due. "Schlummert ein" from "Ich habe genug" is a remarkable, tasteful, and surprising movement that could have been all too easily tossed off to highlight the rest of the movement. While the vocal artistry on this album is phenomenal, it is matched (if not surpased) in pure beauty, sensitivity and expressiveness by the instrumentalists. On this point, Marie-Andrée Benny's flute performance in "Ich habe genug" is especially noteworthy- she deserves mention on the cover of the CD.
But, the highlight of this recording is the Psalm 51, which is unfortunately too often ignored (it was discovered rather late as far as works by Bach go, and its "Lutheranization" may strike some as unseemly). However, to ignore this recording to prefer the original without having heard Bach's rendition (especially by the Violons du Roy) is a mistake. Not only is it one of the most sensitive recordings given to this music (the tempi perfectly underscore the drama of the music, an accomplishment that the suffering-inducing slow tempi of many of the most highly regarded recordings of the Stabat Mater completely fail at), but Bach's subtle enhancements of Pergolesi's original score yield a version that is more lush, confident, and listenable. I cannot recommend this recording more highly.