The interface is clean and the notifications are well-done, with informative little transparencies. However, there are too many little features for the main buddy-list, which makes finding the option you want difficult. Another annoyance is that in order to add new contacts, you have to go into a menu and open up a network specific dialogue. Interacting with a contact is all through context menus, which can also get a bit confusing.
While you can customize the conversation windows, the options are limited, and they are never as clean and functional as one might like. The skins are very limited and don't exactly seem designed with readability in mind. This is a real problem for people who use their instant messengers as work tools.
While I rate the look and feel to be only a 2, remember that Digsby is in beta, so new skins and a more streamlined interface is surely in the works.