TwitterFace looked promising when I first hit the page. It offers the ability to brand your own client page and offer multiple account management across columns would be great for some users. I viewed the example pages first and was ok with the look and feel.
Basically you can insert graphics, create columns of accounts someone may want to see and also provide links to your company sites or media outlets.
I didn’t create an account since I didn’t see the demand since you could place Twitter widgets on any corporate web page as needed to give it a cleaner look. Individuals may like this service however.