Hrm the hammerklavier and Rach 3 are comparable but the fourth ballade is definitely not comparable to the other 2 in terms of difficulty.

The Hammerklavier's demands are different from the Rachmaninoff and in some ways greater than the concerto.  It's not as pianistic as the Rachmaninoff by any means, either, so performance is far from comfortable.  I saw Stephen Beus perform the Hammerklavier live, and while it may have been his highly individual style of playing, the writing was overwhelmingly virtuosic to the point of near unintelligibility in the fugue.  The fugue is not only close to impossible, but its devices and construction are so sophisticated that an adequate performance requires an enormous quantity of cerebral involvement.

The fourth ballade is extremely difficult but not remotely comparable to the other two.

Again with these pointless difficulty threads

gotta love 'em bro lol

all these are difficult in their own right.  it all depends on where your strength lies. 

Burn all these threads about whats harder, its just useless information.

I want you opinion on whihc is harder out of the 3

But why?  It's all relative anyway.

It's like people get sexual pleasure out of creating these threads. It happens all the time.

  and probably more pleasure answering since the debates are endless...