I'm partial to the talking ones, or ones that make animal-like sounds.
The silent ones are still super cute, yes, and I adore the gestures they do... but I feel that if they were to make some sounds (not just squeaking), they would bring their character that much more to life. Its true that some animals make less vocalizations than a human would, but we're talking about half-humans here... so... yeah.
When I get the funds to start building my own partial suit, I plan on having a moving jaw and making lots of bird noises (character is a bird hybrid) but the character can still speak, so I can still speak without breaking character. I think I'd work on making her voice sound a bit crackly or parrot like when I get to that point, too. Iunno. Hope this helps, I can't wait to see what you come up with!