Anton Rubinstein's compositions are known for their massive, virtuoso requirements that capture the spirit of mid-19th-century concertizing. This piece is notable for its heavy reliance on dramatic gestures and thick, orchestral-style textures.
The technical demand lies in the execution of powerful chordal passages and rapid, wide-span octave jumps without sacrificing the melodic line.
Comparable difficulty and character — good candidates for what to learn next.
Allegro Appassionato is rated Henle level 7 of 9 — late advanced repertoire, roughly ABRSM grade 8 and above. In the RCM system it corresponds to about level 9.
You should be comfortable at Henle level 7 — meaning you can already play level 6–7 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 Allegro Appassionato lasts about 5 minutes.
Allegro Appassionato 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 Ballad by Anton Rubinstein, Barcarole No.3; Op.50 No.3 by Anton Rubinstein, Ballade No.2 by Franz Liszt — see the full similar-pieces list on this page.