La Donna is lovely and has a couple of stresses and quirks were you can make it you own, I chose the Cancan and at the last minute swapped to La donna, to be honest though once you have played them for about a month they are all pretty easy.
I found I played them for too long and got a bit lazy though so be careful...
My personal view of graded pices is to avoid them like the plague!!! They are tuneless trash that offers more room for errors because you have to play them so accurately.
Having said that I can appreciate that a) perhaps thats the point, and

if you already understand music, perhaps they make more sense...yknow like someone speaking french to you, you dont undstand, you slightly understand a few words or you get the real point...
for me, im not nearly smart enough for them yet....
But maybe you are...Good luck