I’m familiar with the majority of Chopin editions on your list. I can offer a few comments, but ultimately one’s choice of a study score depends on the criteria that are most important to the individual musician. My own priorities are fingerings that are both plentiful and congenial to me personally and an engraving format that presents the music in a spacious layout; on those bases, I’ve been very satisfied with the editions of Rafael Joseffy published by G. Schirmer (at least for the genres of Chopin that he edited, which unfortunately excludes the etudes, polonaises and sonatas).
Regarding others:
Mikuli was Chopin’s pupil. Consequently, he’s generally regarded as having unique insight into Chopin’s own principles and methods, and his editions are considered to adhere closely to Chopin’s own practices.
Klindworth is one of the most unorthodox editors, in my opinion. I would describe his editions as aggressively overedited; he seemed to have a fascination for finding inner voices in the music and making them explicit in the notation, and he sometimes even changes the durations of notes to serve that purpose. His insights can be illuminating, but I find the result overzealous and indulgent.
The Paderewski editions have the benefit of editorial commentary (concerning matters such execution of devices like trills and appoggiaturas) and extensive notes that inventory, measure by measure, the main discrepancies among the first published editions (and manuscript, where applicable) in details such as note values, articulations and chord voicings; the Henle edition offers such comparisons as well.
The Scholtz edition published by Peters is very cramped in layout, but a new series of scholarly editions is in preparation by that publisher. The Ballades are already available:
https://www.edition-peters.de/cms/englisch/general/produkt.html?product_id=EP7531There’s another new and noteworthy edition, too, edited by Jan Ekier and published by PWM; it’s distributed in the U.S. through Theodore Presser:
https://www.presser.com/marketing/keyboard/chopin/ekier.htmThe first editions published in England, France and Germany are a valuable resource to consult. The University of Chicago has made them available online at
Chopin Early Editions, and the
Chopin’s First Editions Online website has an interactive display that allows three editions to be scrolled, zoomed and compared simultaneously.