I like that we can see all our contacts, even those who haven't been added yet! It's very easy for us (the sales team at work), because it shows you everything about your contact - their email address etc., so its great when contacting someone via LinkedIn or Facebook through alfapeople, since they are already linked up within there system.
The only thing i dislike from this software would be if some people could have multiple profiles set-up under different names/emails but still show themselves once logged onto the main profile page which makes things difficult sometimes. We use Alfappeople mainly internally however now using outside clients too due to benefits of being able to track leads across both systems.