from what i know suntour invented indexed shifting, but didnt have the resources or finance to develop it, & when their patent expired in 83'ish, shimano took the rein & pushed it further. (i think maybe with the 1st. gen. dearhead XT groupo'??)
i do know, that when shimano launched STI in 1990, they had 250+ people working on R&D, suntour had 20..thats why X-Press was a bit crappy i guess. they were a far smaller company, with a dude at the top, who tried to control everything without listening to much what was really going on.
along with index shifting (im sure this is correct-bite me if im wrong!) they also invented microdrive. that was 92'ish, & by then they were at the end of their game really due to a lack of finance (being bought out i think) & resources.
shame really because XC PRO rocked! (& i liked X-Press).
the other company that lost out was campy, who left index shifting in their stuff till way late..
89' Ridgeback 602lx/603
91' Muddy Fox Alu Pro
87' Muddy Fox Courier
86' Muddy Fox Courier
85' Porsche 924!
On the Kona hunt ..