The more modern concerto are harder imo, to memorise and understand. The Rach is written very logically/traditionally, and how the sound moves is obvious and not too tough to accept, but listen to more modern stuff, you personally have to listen to it and play over sections many more times to really be revealed "the way" to play/interpret.
Rach is a good composer for piano, a lot of his stuff is very pianistic to play (feels right on the hands, naturally alteres in volume/tempo through the notes), and progressions throughout the concerto are routine if you have played a number of piano solos from Rach. I think Rach 3 is way too overestimated for the difficulty it presents, there is nothing really shocking in it that isn't found in other piano solo compositions of his. It is just big and full of content, but just because it has lots in it does that means its hard? No, the question for difficulty must come from the pianistic elements of the composition, how well does it fit for playing on the piano. The rach 3 just feels fantastic on the hands, and has a lot of logical form, this makes it just that little easier to learn. There is nothing in that that should absolutely baffle you if you are confident with your technique.
I think if you are still doing grades for your pianio its impossible to learn this , rach concert should be played once you really know your stuff, then you will realise its not too hard as most people say. It is very hard if you haven't filled in all your techniqcal gaps because you have to support quite a lot, any small deficiency will collapse your peformance (you cant get away with decieving playing thats for sure, eg, skipping/mumbling notes, neglecting dynamics etc). Lots more concertos i prefer tough, like Ravels LH one, or the Gershwin in F *drool* lol.
Topic: why is rach3 hard?