I have one and am very happy with it. I've only been using it since December, so I can't help you on the long term pros and cons.
The OM itself is silent, but watch for the noise of whatever pump you will be running it with. Also, I would say make sure you pick the right size pump to get the amount of flow you want.
I have 2 closed loop bulkheads on each side, but I actually went with the 8-way and just had hubby hook it up so that 2 8-way ports go to each closed loop bulkhead. Doing it this way I felt I could create more flow patterns in the tank for not a huge price difference in the grand scheme of things.