I will keep this basic and chock full of my opinions.
First, I have never heard a ceiling speaker I liked, especially not for LCR. By definition, the sound is diffused and can't be associated with what is happening on the screen. FWIW, I don't really like them for surrounds either, but that is usually more a matter of poor placement.
In walls are better, but usually have poor speaker quality, limiting the sound. Personally I prefer standalone for the flexibility