Johann Adam Hiller’s music is largely functional and reflects the transition toward the high classical style. This work is notable for its clean melody-and-accompaniment texture, typical of the era's keyboard sonatinas.
The primary challenge involves managing the clean execution of grace notes and ornaments within the phrasing.
Comparable difficulty and character — good candidates for what to learn next.
Allegro in A major is rated Henle level 3 of 9 — late beginner repertoire, roughly ABRSM grades 4–5. In the RCM system it corresponds to about level 5.
You should be comfortable at Henle level 3 — meaning you can already play level 2–3 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 in A major lasts about 3 minutes.
Allegro in A major 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 Alla Polacca in B-flat major by Johann Adam Hiller, Piano Sonata No. 16 in C major by Wolfgang Amadeus Mozart, 18 German Dances and Ecossaises by Franz Schubert — see the full similar-pieces list on this page.