Overflows. Internal or External

[kien]

Originally Posted by Madreefer

it's going to be taking away 6" of valuable real estate from my fish and corals.

^ this is my take on this.

I had a tank with an internal overflow and I didn't like it for this reason, and for the reason that it made it more difficult to get good flow in that tank. If you can move all your plumbing to one side/end (of the back) of your tank so that it is easy to access the herbie valve you should be OK.