Autumn Leaves Op. 15 provides a more somber and sustained look at the seasonal theme compared to other versions. It is distinctive for its use of lingering, expressive intervals and slower decay.
The main technical challenge is maintaining legato connections through the slower tempo.
Comparable difficulty and character — good candidates for what to learn next.
Autumn Leaves Op.15 is rated Henle level 3 of 9 — late beginner repertoire, roughly ABRSM grades 4–5. In the RCM system it corresponds to about level 4.
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 Autumn Leaves Op.15 lasts about 4 minutes.
Autumn Leaves 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 1st Sorrow Prayer by Jones-Stubbs, Boon, L8 by Jones-Stubbs, 'Piano Suite' from 'A Folk Tale' by Jones-Stubbs — see the full similar-pieces list on this page.