I have the Southard and I love it. It flips nicely. And its the perfect size imo. I would love to get a new scale to replace the brown. I might even try making my own, maybe.
I have both and I love both of them. I think all of the key points have been touched on. So I'll state what I dislike about each. I really dislike the domino's sharp edges on the non-cutting surface of the blade. If spyderco could of just knocked down the spine to match the flipper, I wouldn't have much to complain about. The Southard's clip is disappointing; seems like it was a hasty after thought. Here are some older, recycled photos showing different scales:
