From my view from years ago before 24's became popular... I always saw it as a bike which met halfway for a riders height/build whether they was too big for mod or small for stock. But now it tends to be personal preference really as any build seems to ride any size bike now.
In my time i have rode 3x 24"s
1st onza zoot- It felt horrible to be fair it felt like someone put a onza t-rex in a tumble dryer for the way it rode.
2nd- Modern zoot- It felt ok nice and flicky for doing little tricks and spins.
3rd- Damons old Ozonys unruly 24" ( Which billocks now has) I felt this bike rode awesome... Felt like a average TGS style bike but in 24" form..
Seeing these 24" echos sell at a good price is also very tempting.. Just to have as a spare bike and also try out the 24" scene.
Back in the days of 03-04 there wasnt really many 24s around at the time from what i can remember i think cannondale did one which lance ( guy from tricks n stunts dvd) had one, Ashton edd tongue, onza zoot and if i remember rightly there was a few curtis frames which people used as a 24.
But since the day Inspired started and the danny mac videos were released. 24" has got a lot more popular on the trials scene. But a lot of the 24s were based on a streety/bmx style bike but now a lot of manufacturers have started doing TGS style 24's such as echo and ozonys.
I suppose its personal preference for which you wanna choose.
I suppose with any bike you can " Make it suit" for yourself i.e. changing parts on a later to customise to your standard to make it ride nice or for yourself.
Andy