Dumb question time!
 

Are their significant performance differences between higher end Campy, Shimano, Suntour, and SRAM of equivalent eras? Or is it all just a matter of opinion? I definitely steer towards the japanese groupos base on price to performance.. SRAM I really don't know much about despite having a few of their lower end bits, but they seem well made. The campy stuff that appeals to me is out of my price range (well what I'm willing to spend anyhow), so I haven't had much of a chance to try that either.. so school me on this stuff please :D

If you are talking integrated shifting then campy sucked at it early on (synchro). So in that respect there was a clear performance leader for a few years. That's one example since your question is rather broad.

More in reference to is there a performance increase really to choosing a pretty campy groupset over a plainer looking shimano for instance.. the question is indeed broad but I am curious.

Depends on the era.