What is the difference between low and medium profil?

I'm looking at campy ZONDA vs NEUTRON.

thanks

Weight, aero, stiffness. The lower ones have the weight. The deeper ones are stiffer and more aero. The aero difference is most likely insignificant.

I have Campag Shamal Ultras and can't really tell the difference in comfort between them and my traditional (32) spoked wheels. They sure accelerate nicely though.

Zonda:
24mm/28mm
675g / 935g
1610g

Neutron:
18mm/18mm
660g / 890g
1550g

I would go with the Zonda's and save your money over the neutrons.