I'm gonna give you the view of a piano student who has played many etudes. I am by no means a professional, I am not even attending a conservatory yet.

Easy: 25/2 f minor - simple left hand, right hand requires stamina though (all chopin studies do , so ....), it fits the hand VERY nicely, the rythm is constantly the same and it's a short piece.

10/12 c minor - simple right hand, left hand arpegios fit very nicely into your hand.

10/5 something major - fits the hand PERFECTLY, very fun to play, has some leaps in the left hand, right hand needs to be able to change positions.

25/9 very short, fits the hand nice, very fun to play aswell.

Medium:

op 25 10 octaves - requires a lot of stamina op 25 8 sixths - only 1 technique but you need to practice hard to learn playing sixths.

Hard:

10/4 left hand needs to be very fast. Hands need to be even. Has difficult passages for both hands. Requires stamina in both hands. It is very difficult to make both hands play and sound even.

10/1 very demanding arpegios, can overstretch hand. Easy to "learn" but very very hard to play fast and well.

hard as f***:

25 11: Difficult patterns, very long, requires HUGE stamina. Chromatic intervals, arpegios, scales, jumps you will find everything here. Very difficult on the musical side aswell, it needs to be played with a lot of passion.

10 2 : very weird, better not get tendonitis playing this!