Oh dear... I was initially thrilled with the new color options, specifically "track follow bus color selection". 
But it appears that you can only select the foreground color of clips (both midi and audio) now. Seriously? The background has to be ugly black?
Tell me, is there any way to retain my clip colorization that I had in X2?
e.g.

 
I know, I know, some people just can't be happy. 
But seriously, if this is not longer possible, I'm rather saddened.
I HATE the black clip backgrounds. 
 
Please let me be missing some option here...

You can set the background and foregrounds of the colors in the clips menu like always.

Are you talking about the area where there are no clips?

No, I'm just talking about the clips. It appeared that there no longer existed any color option for clip backgrounds, except for "clip background (selected)".
 
I'll take another look...
 
Clip background color options are definitely missing from the Edit > Preferences > Color panel and can't be set up as default for tracks 1,2,3...10 any more.
 
However, I see that I can change the clip background/foreground from the Track Inspector, just as in X2.
 
I suspect I can live with this... I'll have to experiment.
 
When I saw the video, I thought the feature involved a user-defined swatch panel which included both foreground and background colors. Which would have been nice...

Maybe they are still in the inspector? In X2 you could find those options in the inspector.

You can set the clip colors in the Clip Inspector, but it's a step backward, because you can't just set up the Tracks 1-10 the way you like them and select 1,2,3,4... etc.
 
You have to actually select foreground/background independently. And the swatch is useless for this. So although I like the color tinting on the console/track panes, I really don't like the effect it has on clip colors. I haven't decided how I feel about it. It's my fault for assuming it would work the way I envisaged.

Why not just EXPORT that color set in X2 and then IMPORT it into X3?
 
Should work as it always had.
 
Steve