I just tracked a project at 24/88.2, first time I've went higher than 48Khz.
first think I noticed is that I can't run nearly as many plugs, which is probably a good thing...
This project is turning out to be the most "hi-fi" sounding thing I have tracked so far. i'm not sure if that is entirely due to the 88.2 sample rate or the way it was tracked cuz I experimented with some new gear/mics/mic placement... but yeah, just lots of clarity and seperation that I have struggled to achieve with other projects...
I dunno, I guess my advice would be to try it and see for yourself, or more importantly, see if you notice a difference.