Mozart's K. 533/494 sonata is a mature work, blending thematic material from an earlier sonata (K. 494) with new movements, creating a work of considerable depth and sophistication. It is known for its contrapuntal intricacies and expressive melodic lines.
Mastering the rapid scales and arpeggios while maintaining clarity and a singing tone is crucial.
3 Keyboard Sonatas (Op.5) 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 7.
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 3 Keyboard Sonatas (Op.5) lasts about 25 minutes.
3 Keyboard Sonatas (Op.5) is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.