I have a Peugeot Versailles that was sold with indexed Shimano Light Action downtube shifters. Truly fine shifting. Downtubes have the least amount of cable, so shifting, IMHO, is crisper and more accurate than other placement. Depends on usage. For racing and general usage, I prefer downtube for the accuracy. For touring (even though I'm retired from any distance touring,) I prefer bar end shifters or grip shifters on those bicycles. For mountain, I'm still using thumbshifters, because it is what I'm used to.