Overflow debate

[GQsmooth]

I'm building a new 220G, just unsure of what kind of overflow to go with as I find that there's pro's/cons's to both internal/external. I'm leaning towards external as I don't want to take an extra 20"x6" of space inside of the aquarium.

The 100G sump will be located in the basement, I found an overflow called the synergy overflow which attaches to the glass on either side using bulkheads with external acrylic box which I think is better than siliconing a glass external overflow(will be a lot heavier and cause more stress IMO).

http://synergyreef.com/product/20-sy...reef-overflow/

Thoughts?