The big difference is the level of aftermarket support.

I built a 180SX track car for a mate, and literally it was catalogue shopping, the most fabrication that i had to do was to rivnut mounting points on for attachments. Thats it, everything was bought and just fitted.
Compare that with the AE86 and even my MA61 where ive easily spent more time fabricating things as i did on the entire 180 build.