I used to put all my '90s Campag cranks on square Shimano BBs, and it worked ok, but
now all the cranks are 'stretched' and go on way too far on a Campag square spindle (the cranks easily hit the cups). I was going to sell some of them, but now they're a bit knackered

also, the Campag cranks with the auto extract bolt need checking more often on a Shimano BB
(I guess because they just don't go on far enough), especially after the first few rides