Marietta is a Steinway Artist and has a successful live CD series on the Bloomline label, as evidenced by five-star reviews in NRC Handelsblad for the Chopin and Schumann piano concertos and in Luister for the Liszt sonata: "With an unquenchable inner fire, both the devil's art and poetry find their way under Petkova's nimble fingers". On her CD 'En Face' she plays Bach and Beethoven, recorded live at the Amsterdam Concertgebouw. In 2017 she released the 24 Preludes by Skrjabin and Chopin. Her latest album (late 2019) with the 24 Preludes by Debussy marks a new milestone. These cds again elicited superlatives from the press. "Two CDs that compel breathlessness, because it seems as if the soul of Debussy really sings", according to Listen.