I have a Synergy and do not recommend it. It's loud and the lid develops lots of salt creep. If there is too much flow through the drains the external box expands and the lid won't stay on.
Based on all this information. I’m leaning toward the Modular Marine. I like the exotic marine but the smallest unit can only handle 1200 gallons and it’s still as big as the MM. Let me know if I’m wrong. It looks like the MM vendor isn’t available for a couple days anyway.