Well if I had to do it again I would go with the 5000 int. As with all octopus stuff I had to silicone all the connections because they leak, even with gaskets in place. I have had to do this with all 5 octopus pieces I own.
Once you get it dialed in it works great. My 2 main concerns with it are that when you first turn it on after cleaning you have to turn the water flow way down, or it will overflow. (I have concerns about what happens if my power goes off and then back on when I'm not home). Secondly, it pulls enough stuff that the holes in the lid crust over, not allowing the air to escape and the bubbles actually push the lid off and the gunk starts coming down the side. I have something wedged between the top of the lid and stand to keep it tight. I clean it about every week and it pulls tons of stuff.
Over all it is a great skimmer. If I had to do it again I would definitely keep the sro, just would go internal instead.