Are you kidding? TouchWiz is intuitive and smooth?
Samsung's a lot lighter and smoother than Sense. Not sure about these to-be released software packages bundled with their skinned android, but as far as past experience goes I can safely say, after using and experiencing both, that Touchwiz is much lighter on the OS than Sense. Sense is rather slow and a resource hog. I like the appearance of Sense and I do like there's some cool features, and I do think Touchwiz has many gimmicky features, but I think if I had to choose, I'd go with Touchwiz over Sense.
Preinstalled software aside, the Samsung community is much larger so there's more custom ROM packages to choose from.