Géza Zichy was a notable one-armed pianist, making this work a fascinating study in keyboard economy. It is characterized by its sophisticated harmonic language and idiomatic writing for the left hand.
The primary challenge lies in achieving full, orchestral sonorities with a single hand.
Comparable difficulty and character — good candidates for what to learn next.
Allegretto grazioso is rated Henle level 5 of 9 — late intermediate repertoire, roughly ABRSM grades 6–7. In the RCM system it corresponds to about level 7.
You should be comfortable at Henle level 5 — meaning you can already play level 4–5 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 Allegretto grazioso lasts about 4 minutes.
Allegretto grazioso 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 Body and Soul by Johnny Green, 12 Variations in B-flat major by Wolfgang Amadeus Mozart, Béatrice by André Messager — see the full similar-pieces list on this page.