I used to use Hanon a lot, but as you said, it gets mundane and unhelpful after a while. Transposing the exercises to different keys helps a bit, but you really can't get into it very much.
The Brahms 51 are interesting. It's somewhat like Hanon in the repetitive style of one measure leading into something similar happening in the next, but unlike Hanon, both hands are not doing the same thing at all times. You pretty much need a full-sized piano for parts of it, though -- the octave and arpeggio exercises are particularly space-consuming.
Topic: New excersises