The differences between both in space are basically the same as on land:

• Coil guns are harder to build. Railguns are easy.
• Coil guns get more kinetic energy into the projectile than railguns for same power and barrel length.
• A salvo from either will overload any shield on a space ship and then penetrate the hull.

The differences between both in space are basically the same as on land:

• Coil guns are harder to build. Railguns are easy.
• Coil guns get more kinetic energy into the projectile than railguns from the same power available and barrel length.
• A salvo from either will overload any shield on a space ship and then penetrate the hull.

A big reactor is needed to fire either. You're talking 100kwh of power per slug sort of thing. A 100MW nuclear reactor could fire one round every 3.6 seconds.