Not saying a properly installed and setup HOB overflow doesn't work just sharing my experience.
I flooded my basement with 100 gallons 3 times in the past couple months whilst using an eShop HOB overflow. It appears as if the flow from the return pump on my 'fuge is insufficient causing the siphon to slowly lose siphon and break. I ordered a new refugium from Glass Cages with a built in overflow. The need to match flow to drain is to me ridiculous and not mentioned anywhere in directions not to mention LifeReef.com says explicitly that matching flow is not necessary. I don't know who or what to believe. All I know is a new tank with a built in overflow is on it's way and I will never try to use a HOB overflow again. If you do just bear in mind that although many, many folks have never had a problem other people have. For what it's worth when I told Randy, the owner of Life Aquatic in New Canaan CT, that I was installing a HOB overflow his comment was "oh, you mean one of those boxes that floods your floor." Apparently he has had similar experiences with his customers as well.