As you said, they are all wonderful.
Although Schumann composed it for his children (perhaps this explains why there are almost no recordings of them), and divided it into two parts (1 –18 – for the little ones; and 19-43 for the more grown-up ones) I don’t think of them as children’s pieces at all – One can see all of Schumann’s music in them.
It is also possible to treat the 43 pieces as a cycle – exactly like most of Schumannn’s piano works. Here is what Michael Endres (who recorded the whole set for Arte Nova) has to say about them:
“The cycle is a totally shattering profile of spiritual development, beginning with the innocently naïve and childish nos. 1 – 5, where no shadows are yet to be found. With no. 6 comes the first small cloud (The poor orphan)[…] with nos 12 and 13 the cycle leaves behind […] the child’s world. […] in the second section, the tone changes, with a contrast between the friendly A major of nos. 20, 22, 24, and 28 and the intervening pieces like the sad no. 19, the magnificently inspired nos. 21 and 26 the sinister no. 23 the excited no. 25. […] [the last] ten numbers are wonderful examples of the uniquely introverted worlds of late Schumann."
This is most excellent piano music.
My favourites:
no. 13 (May, beautiful May)
No. 14 (Little Study)
No. 28 (Remembrance)
No. 30 (***)
N. 32 (Scheherazade)
No. 35 (Mignon)
In fact I don’t think these pieces would be out of place as a very last encore - especially if the programme was particularly hair raising. The contrast would have great dramatic value (Horowitz actually used to do that, he often played Traumerei as an encore).
Best wishes,
Bernhard.