Pro and cons of different styles of over flows

[sully08]

Turned my 220g into a salt tank with 2 internal overflow boxes, each one is 24" long x 6"x 6" and I have them up in the corners. I drilled 3" holes for each box for the bulk heads and 2" pipe goes down to the sump. Over flows work great. If I had my choice I would have external overflows to give the tank a real clean look.