I just came from the unfortunate Gibson escapade where Cakewalk Sonar is no longer going to be supported or developed for. Thanks to the Studio One crew for the warm welcome! For this thread, I can say, coming from Sonar, the very first thing I was impressed with were the seriously resizable faders, something I'd begged CW for but never could gain any ground. However, what keeps me returning to Sonar is the 3-dimensional GUI, and a theme I worked for weeks creating. Studio One (forgive my criticism) has a very paper-flat interface that makes me feel I have to lean into it in order to feel part of it. Some of this is due to the strong colors that obscure features, small text in some places, a 2D vibe with fine, hard-to focus lines to separate functions/buttons, etc. It's easier on the eyes than Sonar's Tungsten theme, I'll grant. I think where Studio One simplified graphics in order to clean up the GUI, actually made some functions less obvious.
Colors are another thing I've noted right off. They're a bit too bold in almost every case, requiring Saturation adjustment, there's limited color choices, and not much in the way of customization. Layer colors are a bit overwhelming since they don't follow Global color settings.
It does appear this is a highly requested avenue for Studio One, regarding custom colors and themes--maybe even graphics? CW released a really slick editor, which I was surprised at exactly how much could be customized. Now, this could be the result of doing things an old-fashioned way, but if you look at this pic, you can see what was possible. This was a theme I created in Sonar. Very easy on the eyes, and warm, even when using cold colors.
(Sidenote: Thanks to Presonus for allowing pictures to be uploaded directly! :)