It's cool to see how he changed from romanticism to ugly.
Some of Scriabin's most beautiful music was composed in his later period. I would hardly consider any of it ugly.
Favorite pieces:
Op. 65
Sonatas: 3, 4, 5, 7, 8, 10
Op. 74
Poem of Ecstasy (Remains my favorite orchestral work to this day)
Concerto (Surprisingly hated by Rimsky K and adored by Liadov)
Fantasy
Op. 69
Poeme-Nocturne
I have doubts to weather or not Scriabin could have finished the Mysterium, which supposedly was intended to be a 7 day synthesis of all arts (This would include visual arts, auditory arts, philosophy, dance, etc.) where the dancers would, at certain times, play instruments and musicians would dance. All of this with a cast of 100,000 people.