Which is better to have? A Ballast thats part of the lighting system or one that has the ballast attached with a cable?

I'm trying to figure out which system to get. They're 400 watt both hps & mh in one setups.

za Stooj
Stooj Reviewed by Stooj on . Internal Ballast vs Ext. Ballast Which is better to have? A Ballast thats part of the lighting system or one that has the ballast attached with a cable? I'm trying to figure out which system to get. They're 400 watt both hps & mh in one setups. za Stooj Rating: 5