I agree with Martykl in that you are better off doing your set up manually. It may be a little more work, but the results and experience you gain will be well worth the effort. You won't be at the mercy of using "What ever they give you in the box." I've owned Velodyne subs in the past but haven't used the SMS-1. As far as the Behringer goes, what I can tell you is that it is a little intimidating, at first, but if you sit with it for about 1/2hr to 1hr, it will all start to make sense. You have to learn how to use the menu system they give you. It doesn't take long because, for all the features, it surprisingly makes good sense in how everything is laid out. Another advantage is that its not designed for 1 specific task. In all likely hood, you will many other uses for it, as well (Especially in a theater setup).
Beyond that, its up to you. But I think most would agree that it would make sense to keep your SSP since its nowhere near your weakest component; probably just the opposite.
