You probably know this already, but the basics of brake maintenance should be applied before buying new stuff. Clean rims, properly set up straddle cable, shoe alignment, etc... Are the cables and housings good? The biggest offender is usually old, hard shoes. They can often be made substantially better by grinding/filing down to fresh rubber. A new set of Coolstops is around $25. None of that is anywhere near as fun some new Paul cantis! As far as retro, the Mafacs and any early Shimano would look right on an 80s bike. Paul makes what I would call a modernized Mafac copy that is super cool.