Robert Volkmann was an important contemporary of Brahms whose works often possess a rugged, intense character. This caprice is technically demanding, requiring quick shifts in registration and dynamic intensity.
Mastering the rapid, sweeping arpeggios that cross over the keyboard is the essential technical hurdle.
Comparable difficulty and character — good candidates for what to learn next.
Allegretto capriccioso (Op.15) is rated Henle level 6 of 9 — advanced repertoire, roughly ABRSM grades 7–8. In the RCM system it corresponds to about level 8.
You should be comfortable at Henle level 6 — meaning you can already play level 5–6 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 capriccioso (Op.15) lasts about 4 minutes.
Allegretto capriccioso (Op.15) 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 Allegretto capriccioso by Robert Volkmann, Ballade and Scherzetto by Robert Volkmann, Caprice espagnol by Moritz Moszkowski — see the full similar-pieces list on this page.