As it stands, unread counts are appended with a (...) value.

That is only for mentions though. Also, I think colours work more intuitively if you want to check whether someone talked or mentioned your nick (as opposed to how many)

How should colors be handled, though? Should it match the colors in the ColorScheme used internally? or should it match the Holo/Material colors?

Addendum: I ask this because I've made it a point to try and make colors readable under as many conditions as possible. There's a few edge cases that make this particularly hard to handle because of things like the CM Theme Engine, Samsung's fucked in the head attempt at a user interface that we call TouchWiz, as well as the additions that Sony has made to the party with the Xperia interface. This isn't including the horrible things that companies like Motorola have done in the past. Since we're using the AppCompat theme, it gets a little better, but when you throw in that the AppCompat theme is basically ignored in api21 and above (android 5.0+) you can throw all the things Appcompat gives us.

For a prime example of "Why this doesn't work very well sometimes", look no further than the user selector when you have nick coloring turned on.

it looks kinda bad. It's not staying.

Unfortunately I don't have access to many different devices, it's just my phone I'm afraid. You do have a point though. Perhaps it's necessary to theme the dialog as well? As I wrote it now, it just uses the colours from the color scheme.