Piano concertos

I have not learnt both of these concerto movements, but I love these two concertos very much, so hope I can answer your question.

I think Schumann's concerto is easier.

Grieg's concerto:
it consumes the soloist lots of energy. The concerto also has many Norwegian elements, which may be very difficult to play the real feelings of them.

Schumann's concerto:
As the previous answer states, it is easier for notes. Moreover, the effect that the concerto gives, is just brilliant. (You give a very good feeling for just a easy level of techniques!!!)

For me, I think the Schumann one is easier for notes. But actually, every piece is difficult and it depends on how u manage.