C.P.E. Bach's works are renowned for the 'Empfindsamkeit' or sensitive style, featuring sudden shifts in mood and dynamic contrast. This Allegro is distinctly marked by unpredictable turns and an emotionally volatile melodic line.
The primary challenge is executing the highly expressive, improvisatory dynamic shifts and ornaments.
Comparable difficulty and character — good candidates for what to learn next.
Allegro in A major is rated Henle level 4 of 9 — intermediate repertoire, roughly ABRSM grades 5–6. In the RCM system it corresponds to about level 7.
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 Allegro in A major lasts about 4 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 Solfegetto in C minor, H 220 by Carl Philipp Emanuel Bach, Canzonetta con 6 Variazioni, H.275 by Carl Philipp Emanuel Bach, Allegretto con variazioni, H.65 by Carl Philipp Emanuel Bach — see the full similar-pieces list on this page.