This waltz is an arrangement of themes from Johann Strauss Jr.'s operetta Cagliostro in Wien. It features the characteristic rhythmic flair and charming melodic structures typical of the Viennese operetta tradition.
Students must balance the rhythmic drive of the Viennese waltz against the ornamental melodic passages.
Comparable difficulty and character — good candidates for what to learn next.
Cagliostro-Walzer(from Cagliostro) (Op. 370) is rated Henle level 4 of 9 — intermediate repertoire, roughly ABRSM grades 5–6. In the RCM system it corresponds to about level 6.
You should be comfortable at Henle level 4 — meaning you can already play level 3–4 pieces cleanly. Learning it one level early is possible as a stretch piece, but more than that usually leads to months of frustration.
A typical performance of Cagliostro-Walzer(from Cagliostro) (Op. 370) lasts about 8 minutes.
Cagliostro-Walzer(from Cagliostro) (Op. 370) is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.
Pieces at a comparable difficulty and character include Alexandrinen-Polka by Johann Strauss Jr., 'Deutsche' Walzer by Johann Strauss Jr., Bouquet-Quadrille by Johann Strauss Jr. — see the full similar-pieces list on this page.