I second every part of this. the Color Merge was great to work with, nice saturated colors, speed, eh, but slow changes are gorgeous.I have used the HES version, called a Color Merge. It's an older product, and it doesn't have an amber filter, which I think the SeaChanger does. It's a bit slow in transitioning between colors, but that's really a minor inconvenience. I do like the color saturation of the HES.
Never used or seen a seachanger in person.