These are personal, delicate sketches composed for the Princess Marie, reflecting Liszt's private musical language. The music is characterized by subtle modulations and a deeply introspective, lyrical quality.
The main challenge is achieving a seamless transition between complex inner voices.
Comparable difficulty and character — good candidates for what to learn next.
Albumblätter für Prinzessin Marie von Sayn-Wittgenstein (S.166m) is rated Henle level 5 of 9 — late intermediate repertoire, roughly ABRSM grades 6–7. In the RCM system it corresponds to about level 7.
You should be comfortable at Henle level 5 — meaning you can already play level 4–5 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 Albumblätter für Prinzessin Marie von Sayn-Wittgenstein (S.166m) lasts about 3 minutes.
Albumblätter für Prinzessin Marie von Sayn-Wittgenstein (S.166m) 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 Ave Maria in G by Franz Liszt, Ave Maria IV, Solo piano by Franz Liszt, Blume und Duft by Franz Liszt — see the full similar-pieces list on this page.