I've heard some reef people say they don't think the Sea Clones are as effective as other protein skimmers. I've also heard they're noisy. I don't have any experience with them, however.
I just bought the Marineland SOS overflow, and boy do I like it. It has an adjustable siphon on the drain, and it really IS silent. I was in the process of making a DIY overflow, but I found out yesterday that a local pet shop was having a clearance sale--live rock $3.50/lb and live sand $1/lb. The sale ended that day so I essentially had to buy an overflow or let it go. Bought it for $89 and I still saved about $100 by getting the live rock even with the materials I had already put toward my DIY overflow.
There is one problem with the overflow, however: the u-tube is plastic and was manufactured in two parts then glued together. Mine came out of the box with a slight air-leak on the seam. Its a very slow leak, but I put a bead of aquarium silicon along the seam to be sure it never loses its prime.