Visully S8.5 and earlier versions are more visually pleasant to work with.
Not here - I much prefer X1's UI over previous versions. I would still like the ability to color CV strips ala PT, but otherwise I really do prefer the way X1 looks. I haven't loaded X2 yet, but from what I saw on the Webinar they've made some minor tweaks that look nice.
In the end, color just might be the most subjective aspect of SONAR or any other DAW. Visit the S1 forums some time - it's a similar situation where users frequently have questions/requests about the the ability to change colors (you can't). Personally I think S1 has a sharp looking UI, though some of the icons and tools are a little small for my tastes. And its color scheme? Grey and blue. Go figure.